Winter has come early to the Island Alps and while lower elevations have "below threshold" amounts of snow for avalanche hazard, at the higher elevations and on smooth ground cover, the potential exists. With more snow in the forecast hazard will become more widespread.

The Vancouver Island Avalanche Bulletin will start posting forecasts as hazard becomes more widespread and funding allows.

In the meantime please read this informative blog about early season conditions by Avalanche Canada forecaster James Floyer.

Take it easy out there. We've got a long season of riding ahead of us!

This Bulletin Valid Until: Saturday April 16, 2017 @ 6 pm. 

Confidence:  Moderate- limited alpine snow pack observations

Main Concerns: (Avalanche problems)

Wind Slab-   Over 28 cm reported in the last 48 hours accompanied by moderate south east wind have formed wind slab in both the alpine and treeline. These wind slabs will initially be touchy to light triggering but are expected to settle and bond. At higher elevations expect in isolated areas with excellent protection from the sun these wind slabs to remain active during this forecast period. Wind slabs will be found on lee aspects (North west thru to North east) and located in terrain features such as at the base of steep cliffs, below any cornice features, ridge top areas and steep convex rolls. Avalanches from wind slabs could be large (size 2).

Cornice-   Past precipitation and wind combined with warm temperatures have provided ideal conditions to continue to form and grow cornices.These hazardous snow features can be found on ridge tops and on primarily north west thru to north east aspects and in both the alpine and at treeline. As temperatures and freezing levels rise cornices will be fragile, unpredictable and when failing will deliver a heavy load to slopes below and may trigger in isolated terrain a much larger avalanche (size 3). Give these hazardous features a wide berth if deciding to travel either above or below them.

Loose Wet-  These avalanches will become prevalent on Sunday as temperatures begin a rapid rise and the sun will be in full effect. Loose wet will be found on all aspects but especially solar and at all elevations tree line and below. Loose wet avalanches could gain enough mass be large in size (size 2) and will be very touchy to human triggers during the height of daytime warming. Loose wet avalanches are likely to be touchy to human triggers in steep, thin, and unsupported terrain features and when exposed to sun will become immediately unstable and very touchy to triggering.

Travel/Terrain Advice: Freshly loaded lee slopes will remain unstable during and after snowfall expect a rapid change in snow pack on Sunday due to rising temperatures and solar effect on the upper snow pack. Evaluate snow and terrain carefully and identify features and areas of concern. Plan to avoid steep open slopes and unsupported features,choose simple terrain that avoids over head hazards. Be aware of your position within the terrain as even a small loose wet avalanches may have enough mass to push a skier or hiker from a safe stance into hazards such as cliffs or crevasses below.

Past Weather: Over the last 72 hours, mountain alpine weather has seen air temperatures swing from minus six to zero degrees.A total of 30 centimeters has fallen with moderate south east wind.

Avalanche Summary:  Ski cutting on steep west aspect terrain at tree line was touchy and produced numerous small (size 1 ) wind slab with crowns down 20 cm and propagating easily.Day time warming produced widespread loose sluffing and point releases of the upper surface snow on all aspects with the exception of due north. 

Snowpack Description:  Moderate temperatures, new snowfall and freezing levels rising mid day to above 1500 meters is settling new snow rapidly and producing almost daily, a surface crust. A total of over 100 centimeters has fallen above 1000 meters in the last week and a number of shears within this upper snow can be found at varying depths and are producing moderate resistant planar results when tested. The shears are found to be failing on a density change with preserved snow between at least two identifiable well settled slabs. The melt freeze crust buried on April fourth is as well producing moderate resistant planar results and can be found down between 80 to 100 cm and likely deeper than 100 cm in isolated lee aspect terrain. Below this crust a variety of both sun crust and wind crust have been observed and are dependent on orientation to both the sun and wind. 

 Three significant crusts exist in the mid snow pack with the mid February down approximately 250 cm and this being the most pronounced and supportive with facets still being found above and below this crust.The lower mid and lower snow pack continue to settle and with this settlement an increase in density and strength had been noted.

Surface- New snow has buried a well developed surface crust.

Upper-  Numerous melt freeze crusts exist in the upper snow pack.

Mid-  Well settled with lingering persistent weaknesses found between 100 and 200 cm 

Lower- Well settled.

Weather Forecast:   A low pressure centered off the north west of the forecast area continues to push storm pulses east, bringing moderate south east wind and light snowfall. Expect this system to dissipate early Saturday, and in its wake a ridge of high pressure will bring to the region clearing sky and north wind. Sunday will see solar effect at its strongest and alpine temperatures and freezing levels will begin to rise rapidly before mid day.

Fri- up to 15 cm new snow.  Winds SW to 40 km/hr.                                                  

Freezing level to 1200 m.

Sat- up to 5 cm new snow. Winds S to 25 km/hr.                      

Freezing level to 1200 m

Sun- Clear sky  Winds NE to 15 km/hr.                                                    

Freezing level to 1500 m. 

Prepared by Jesse Percival

This Bulletin Valid Until: Wednesday  April 12, 2017 @ 6 pm. 

​

Confidence:  Moderate-  limited alpine observations 

Main Concerns: (Avalanche problems)

Wind Slab-  Past very strong gusting to extreme south winds and up to 60 cm of new snow during the last forecast period has formed dangerous wind slabs in both the alpine and at tree line. Wind slabs will be found on lee aspects (North west thru to North east) and located in terrain features such as at the base of steep cliffs, below any cornice features, ridge top areas and steep convex rolls. Avalanches from wind slabs could be large (size 2) and will be touchy to very touchy to light human triggers as snow fall amounts continue to increase and winds persist. 

Storm Slab-  A storm slabs in both the alpine and at tree line has formed from past precipitation of up to 60 cm in many places this storm slab can be defined as a hard slab. These storm slabs have been found on all aspects and expect to find these dangerous avalanches to be prevalent in areas that offer protection from the wind. Avalanches from storm slabs could be large to very large  (size 2-3) and are stubborn to light human triggers. When trigger, expect storm slabs to run fast and far and with widespread propagation.

Cornice-  New snow, wind and moderate temperatures have provided ideal conditions to form and grow cornices.These hazardous snow features can be found on primarily north west thru to north east aspects and in both the alpine and at treeline.As temperatures rise and snow fall and wind is forecast to increase cornices will be fragile, unpredictable and when failing will deliver a heavy load to slopes below and may trigger a much larger avalanche (size 3). Give these hazardous features a wide berth when deciding to travel either above or below them.

Travel/Terrain Advice:  Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended and should be avoided. If users choose to travel in to avalanche terrain plan to avoid steep open slopes and unsupported features,choose simple terrain that avoids over head hazards.

Past Weather: Snowfall and strong south east winds continue to keep mountain snow pack conditions from moving into a spring melt freeze regime. Up to 60 cm in the past week has fallen on a wide spread surface crust and strong winds pressed the upper snow pack turning in specific areas this snow into a hard slab. Mid day temperatures did rise on Saturday and the upper snow pack became moist all aspects and elevations 2000 meters and below.   

Avalanche Summary: Avalanche control teams using explosives produced numerous large (size 2- 2.5) avalanches on north and west aspects. These avalanches had crowns between 40 to 80 cm in depth and where primarily hard storm slab. Initially these avalanches where stubborn to triggering but in specific areas below ridge tops became touchy. Once these avalanches where triggered, they propagated far and wide and the avalanches ran to the bottom of there paths, with some running past historic run outs.

Snowpack Description  New snow of up to 60 cm has buried an upper surface crust that is up to 10 cm thick and was supportive to foot penetration.This new snow has settled rapidly and displays slab properties, it is however bonding well to this crust but when trigger has a high probability of propagating far and wide.Below this new snow and new crust a variety of both sun crust and wind crust have been observed and are dependent on orientation to both the sun and wind. 

 Three significant crusts exist in the upper mid snow pack with the mid February down approximately 250 cm and this being the most pronounced and supportive with facets still being found above and below this crust. The mid February crust has produced hard resistant planar results when a deep tap test was performed and continues to persist and remain a layer of concern.  As temperatures have remained moderate and upper snow pack height and weight increase, recent test profiles have shown the other crusts beginning to decrease in density and a lack of planar results between the crusts and interfaces above and below them.The lower mid and lower snow pack continue to settle and with this settlement an increase in density and strength had been noted.

Surface- New snow has buried a well developed surface crust.

Upper-  Numerous melt freeze crusts exist in the upper snow pack.

Mid-  Well settled with lingering persistent weakness found between 100 and 200 cm 

Lower- Well settled.

Weather Forecast:  Spring weather is in effect, incoming storms are less organized. Forecast models have begun to predict a decrease both in the intensity of winds and precipitation amounts, while temps and freezing levels are on the rise.

Mon- up to 30 cm new snow.  Winds SE to 50 km/hr.    Freezing level to 1000 m.

Tue- up to 5 cm new snow .    Winds NE to 25 km/hr.   Freezing level to 1400 m.

Wed- up to 25 cm new snow   Winds SE to 25 km/hr.   Freezing level to 1100 m. 

Prepared by Jesse Percival

This Bulletin Valid Until: Friday April 7, 2017 @ 6 pm. 

​

Confidence:  Moderate-  high variability between forecast wind and precipitation amounts on Friday  

Main Concerns: (Avalanche problems)

Wind Slab-   Moderate to strong south east winds and up to 70 cm of new snow during this forecast period will form dangerous wind slabs in both the alpine and at tree line. Wind slabs will be found on lee aspects (North west thru to North east) and located in terrain features such as at the base of steep cliffs, below any cornice features, ridge top areas and steep convex rolls. Avalanches from wind slabs could be large (size 2) and will be touchy to very touchy to light human triggers as snow fall amounts continue to increase and winds persist. 

Loose Wet-   Upper surface snow will begin to lose cohesiveness as rain is forecast to fall at lower elevations, forming loose wet avalanches. These avalanches can be found on all aspects but especially solar and at all elevations tree line and below. Loose wet avalanches when triggered may gain mass as they travel and have the potential to be large in size (size 2). Expect upper snow pack loose wet avalanches to be near certain to occur during warm storm periods and when rain falls on new snow. Loose wet avalanches are likely to be touchy to light human triggers in steep, thin, and unsupported terrain features and when exposed to either rain or sun will become increasingly unstable and very touchy to triggering.

Storm Slab-   Moderate to strong snowfall amounts are expected to deliver up to 70 cm of snow throughout the forecast period and will likely form storm slabs in both the alpine and at tree line. Storm slabs will be found on all aspects and expect to find these dangerous avalanches in areas that offer protection from the wind. Avalanches from storm slabs could be large (size 2) and will be touchy to very touchy to light human triggers as storm snow fall amounts increase. 

Travel/Terrain Advice:  Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended and should be avoided. If user choose to travel in to avalanche terrain, choose simple terrain that avoids over head hazards.

Past Weather: Warm temperatures, followed by a cooling trend with near sea level freezing levels has developed a supportive melt freeze crust. Beginning Tuesday new snow fall had buried this new crust.

Avalanche Summary: No new avalanche activity reported in the last 72 hours.

Snowpack Description  New snow has buried an upper surface crust that is up to 10 cm thick and was supportive to foot penetration. This new snow is settling under moderate temperatures and displaying slab properties, initial testing yesterday indicated a moderate bond between the new snow and this recently buried crust. Below this new crust a variety of both sun crust and wind crust have been observed and are dependent on orientation to both the sun and wind.

  The March 23 crust is between 80 to 100 cm deep on lee aspects.This crust continues to produce hard resistant planar results when isolated and tested.The mid March rain crust is prevalent on all aspects and elevations, up to 20 cm thick and buried down 120 cm plus under dense well settled snow. The mid February persistent weakness can be found down up to 200 cm in isolated lee terrain in the alpine and is now likely dormant as numerous snow pack tests produced either no results or hard non planar results.The mid and lower snow pack are well settled and very dense snow pack conditions are found. 

Surface- New snow has buried a well developed surface crust.

Upper-  Numerous melt freeze crusts exist in the upper snow pack.

Mid-  Well settled.

Lower- Well settled.

Weather Forecast: A cavalcade of moderately strong pacific lows will continue to pass thru the region with Tuesday night and Wednesdays system looking to be packing the greatest punch. Forecast models predict much higher precipitation amounts on the western edge of the forecast region and throughout the region expect generally milder temperatures, moderate wind and rising freezing levels.

Wed-  up to 20 cm new snow 10 mm of rain. Winds SW to 40 km/hr.                                            Freezing level to 1500 m.

Thur-  up to 20 cm new snow 5 mm of rain. Winds SE to 50 km/hr.                                              Freezing level to 1100 m.

Fri-   up to 25 cm new snow 15 mm of rain. Winds E to 40 km/hr.                                              Freezing level to 1200 m. 

Prepared by Jesse Percival

This Bulletin Valid Until: Sunday April 2, 2017 6 pm. 

​

Confidence: Good

Main Concerns: (Avalanche problems)

Storm Slab-   A settled slab sits on a crust that was buried march 23rd and can be found down 60 and 80 cm in the snow pack. This crust can be found on all aspects and at all elevations below 2000 meters.This storm slab is stubborn to heavy triggers, but if triggered could produce large to very large avalanches(size 2-3)

Cornice- New snow, wind and moderate temperatures have provided ideal conditions to form cornices .These hazardous snow features can be found on primarily north west thru to north east aspects and in both the alpine and at treeline.As temperatures rise and load increases cornices can be unpredictable and once failing will deliver a heavy load to slopes below and may trigger a much larger avalanche (size 3). Give these hazardous features a wide berth when deciding to travel either above or below them

Travel/Terrain Advice:  Dangerous avalanche conditions exist on specific terrain features. Evaluate snow pack and terrain carefully and identify routes that avoid hazardous features and areas of concern. Be very aware of the intensity of solar effect as short periods of clear sky and sun will begin breaking down the upper snow pack and decrease stability. When the sun appears, loose wet avalanches, failing cornices, and storm slab instabilities will become a concern within a very short period of time.

Past Weather: up to 40 cm of new storm snow fell accompanied by moderate south west winds and rising freezing levels. A natural avalanche cycle occurred as temperatures rose and the upper snow pack lost cohesiveness.On Thursday cool temperatures promoted the development of a surface crust and this crust bridged the entire snow pack increasing its overall stability.

Avalanche Summary: A natural avalanche cycle on Tuesday produced numerous small (size 1-1.5) loose wet avalanches on all aspects but where specific to tree line and below treeline. A few loose wet gain enough mass in steep north aspect terrain isolated terrain to create large (size 2) avalanches.

Snowpack Description The upper snow pack is settling well under current mild temperatures and mixed precipitation with the upper surface snow losing cohesion due to those same warm temperatures and rain. Yesterday an overnight cooling period, tightened the snow pack and has increased overall stability. The March 23 crust is now 60 to 80 cm deep on lee aspects.This crust is currently producing hard resistant planar results when isolated and tested.The mid March rain crust is prevalent on all aspects and elevations, up to 20 cm thick and buried down 100 cm plus under new dense well settled snow. That crust is bonding well with very recent hard resistant planar results from a test profile @ 1400 meters on a south aspect. The mid February persistent weakness can be found down 150 cm and possibly up to 200 cm in isolated lee terrain in the alpine and is becoming dormant as numerous testing produced hard non planar results. The mid and lower snow pack are well settled and dense snow pack conditions are found. 

Surface- becoming moist in the pm and firm in the am

Upper-  numerous melt freeze crusts exist in the upper snow pack

Mid-  Well settled.

Lower- Well settled.

Weather Forecast:  Continued unsettled conditions will bring to the region light snowfall, showers and intermittent periods of clearing. Freezing levels begin to drop and temperatures cool as the forecast period progresses.

Fri - up to 10 cm new snow 2 mm of rain.     Winds SE to 40 km/hr.     Freezing level to 2400 m.

Sat-  up to 5 cm new snow 4 mm of rain.     Winds SW to 50 km/hr.      Freezing level to 1400 m.

Sun- up to 5 cm new snow 1 mm of rain.     Winds SW to 40 km/hr.  Freezing level to 1000 m. 

Prepared by Jesse Percival

This Bulletin Valid Until: Wednesday March 29, 2017 6 pm. 

​

Confidence: moderate, uncertainty in forecast precipitation amounts.

Main Concerns: (Avalanche problems)

Wind Slab-   Past light to moderate south east and south west wind and up to 60 cm of new snow has formed wind slab in the alpine and at tree line. Wind slabs can be found on lee aspects and located in features such as ridge top areas and steep convex rolls. Avalanches from wind slabs could be large (size 2) and have have been reported to be stubborn to ski cutting but touchy to light triggers in isolated terrain features. 

Cornice-  New large and fragile cornices developed over the past forecast period. Found at ridge top in the alpine and tree line and specific to all north aspects. Cornices were found to be touchy to human triggering and when even he smallest of these hazardous features collapse and fail, they have the potential to trigger deeper persistent instabilities within the snow pack and create large to very large avalanches (size 3)

Loose Wet- New snow with rain and warming daytime temperatures will promote development of loose wet avalanches. Expect to find these on all aspects and at elevations of tree line and especially below tree line. Loose wet avalanches could gain enough mass and be large in size (size 2) and will be very touchy to human triggers during storm periods and when temperatures and freezing levels are on the rise.

Persistent Slab-  This persistent weakness within the snow pack is bonding poorly in both the alpine and at treeline. A layer of low density facets overlie the crust and recent snow pack tests have continued to produced easy results at treeline. The weakness is located down between 80 and 100 cm. On lee aspects (North East and North West) the persistent weakness is suspected to be down 200 cm. Further heavy loading and very warm temperatures may wake this deep instability and could produce very large avalanches (size 3) in isolated terrain. 

Travel/Terrain Advice:  Evaluate snow and terrain carefully, seek to identify features and areas of concern. Be especially aware of increasing danger levels as precipitation amounts increase and temperatures and freezing levels rise. New and fragile cornice development has been noted and travelers must give these hazardous features a wide berth when either above or below them.

Past Weather: Between 20 and 60 cm of snowfall, fluctuating freezing levels and strong south east winds  developed fragile cornices and promoted ridge top wind slab formation on lee aspects. Some daytime solar effect and warming, moistened all snow surface up to 1600 meters with the exception of well protected north aspects.

Avalanche Summary:  Friday, avalanche control teams at Mount Washington reported numerous explosives triggered wind slabs on the March 23rd melt freeze layer and were specific to ridge top in steep mostly unsupported terrain. Crowns from these avalanches where up to 40 cm in depth and large (size 2). Ski cutting teams encountered stubborn conditions with only direct lee very steep unsupported terrain producing small to large (size 1-1.5) avalanches with 25 cm crowns. Numerous natural wet loose avalanches  where reported and occurred when daytime temperatures increased. These avalanches where small (size 1) and found mostly below treeline with some above and were widespread on all aspects.

Snowpack Description:  A melt freeze crust with a thin layer of preserved dry snow above it buried March 23 is down up to 40 cm. This layer is bonding moderately and was touchy to human triggers. The mid March layer is buried down up to 45 cm and snow pack testing did no produce any results on this layer .The mid February persistent weakness is bonding poorly but currently non reactive to heavy surface triggers and snow pack testing produced a hard result under very heavy testing.This lingering concern will produced very large avalanches when woke and will likely remain a concern for the remainder of the season.Beneath this the snow pack is well settled and dense.   

Surface: Settling new snow 

Upper-  A new reactive melt freeze crust buried on March 23rd can be found down up to 40 cm.

Mid-    100 to 150 cm overlie mid February melt freeze crust (persistent weakness)

Weather Forecast:   A continued westerly flow will bring rising freezing levels and moderate snowfall with rain on both Tuesday and Wednesday.

Mon - up to 5 cm of snow   Winds SE to 30 km/hr Freezing level 1200 m.

Tues- up to 30 cm of snow and rain  Winds SE to 50 km/hr Freezing level 1500 to 1600 m.

Wed- up to 40 cm of snow and some rain  Winds SW to 30 km/hr Freezing level 1500 down to 1000 m. 

Prepared by Jesse Percival

This Bulletin Valid Until: Friday March 24, 2017 6 pm. 

​

Confidence: Moderate

Main Concerns: (Avalanche problems)

Wind Slab-  Wind slabs will form in the alpine and at treeline during both Thursday and Friday. Up to 100 cm of new snow and rain at some elevations combined with moderate to strong south west and south east winds will promote the development of these hazardous avalanches. During storm events, wind slabs specific to lee aspects and will be touchy to very touch to triggers and large in size( size 2).

Persistent Slab-  Deep and stubborn. A melt freeze crust formed on all aspects and all elevations in mid February is buried down between 80 and 100 cm. In lee areas in the alpine this persistent weakness has been found down 172 cm in depth. Currently this weakness is stubborn to light surface triggering. When ideal conditions exist to produce enough load to awake this deep instability, it will produce large to very large avalanches (size 3).

Loose Wet New snow and rain at elevations below 1500 meter, will promote development of loose wet avalanches. Found on all aspects and at all elevations  tree line and below. Loose wet avalanches could be large in size and will be very touchy to human triggers during storm periods and when temperatures rise.

Travel/Terrain Advice: Dangerous avalanche conditions exist and travel in avalanche terrain is not recommended.

Past Weather: Moderate to strong south east and south west wind with up to 15 cm of new snow. 

Avalanche Summary:  A few small (size 1) loose avalanches reported all failing within the new snow on steep north and west aspects.

Snowpack Description The upper snow pack is settling well under current mild temperatures and precipitation.The mid March rain crust is prevalent on all aspects and elevations, up to 20 cm thick and buried down 20 cm under new dense well settled snow. The new snow is bonding moderately well with resistant planar results reported. The mid February persistent weakness can be found between 80 to 150 cm and possibly up to 200 cm in isolated lee terrain in the alpine. Above and below the layer facets are present and are a compounding factor of this instability.This layer is producing easy results when isolated and tested. The mid and lower snow pack are well settled and dense snow pack conditions are found. 

Surface- well settled new snow

Upper-  between 80 to 150 cm overlie a melt freeze crust

Mid-  Well settled.

Lower- Well settled.

Weather Forecast:  Unsettled spring weather continues,a series of weak disturbances will spin thru the forecast region bringing light to moderate snowfall and southwest and south east winds. Eastern zones will receive substantially less precipitation more sun effect and periods of clearing between storms, while western front ranges will receive the brunt of the storms with significantly higher precipitation amounts forecast. 

Wed -   up to 20 cm new snow    Winds SW to 40 km/hr.     Freezing level to 1500 m.

Thur-  up to 50 cm new snow      Winds SE to 50 km/hr.      Freezing level to 1100 m.

Fri-     up to 50 cm new snow       Winds SE to 60 km/hr.      Freezing level to 1200 m. 

Prepared by Jesse Percival

This Bulletin Valid Until: Sunday March 19, 2017 6 pm. 

​

Confidence: Moderate: uncertainty in determining above 1800 meters in elevation the current upper snow pack conditions, specifically seeking the existence of the new melt freeze crust and its strength and bonding properties with new snow. The other uncertainty that resides above 1800 meters in elevation is the bonding properties, depth and distribution of the deep persistent crust. Seeking observations and information from public observers. If you have the training, experience and skill level to access alpine avalanche terrain , please forward your observations to forecaster@islandavalanchebulliten.com

Main Concerns: (Avalanche problems)

Wind Slab-   New snow between 10 to 25 cm is expected during this forecast period combined with moderate south east and south west wind will produce wind slabs. Wind slabs will be present in lee terrain and located in features such as ridge top areas and steep convex rolls. With the exception of elevations above 1800 meters wind slabs will be seated on a recently formed hard crust and will be very touchy to human triggers . Avalanches from wind slabs could be large (size 2 )in size and will become very touchy to all triggers when temperatures begin to warm.

Persistent Slab-  This persistent weakness within the snow pack is bonding moderately well at treeline and poorly in the alpine.The weakness is located down between 80 and 100 cm. On lee aspects (North East and North West) the persistent weakness is suspected to be down 200cm. Currently the new melt freeze crust is bridging the upper snow pack, providing this deeper crust with a protective layer from light to moderate loads.  Further heavy loading and very warm temperatures may wake this deep instability and could produce very large avalanches in isolated terrain 

Travel/Terrain Advice:  Very dangerous avalanche conditions, travel in avalanche terrain is not recommended. If users intended to travel in avalanche terrain make conservative decisions, and utilize simple well support low angle terrain. Be especially aware of over head hazards (cornices) and avoid lee areas with deep pockets of fresh snow.

Past Weather:  Rain, warm air and moist surface conditions were followed with a sharp drop in freezing levels and temperatures promoting the development of a melt freeze crust. This very hard surface crust has formed on all aspects and elevations below 1800 meters and boots or skis will not penetrate it. Up to 15 cm of snowfall then fell on this new crust in the last 48 hours combined with moderate Se wind and cooling temperatures.

Avalanche Summary: 

  Tuesday March 14, warm and wet conditions produced numerous natural wet loose avalanches on North steep aspects at treeline and below treeline. These avalanches were large in size (size 2) and a couple of them gathered enough mass to put load on the persistent weak layer , causing a step down and producing slab avalanches between 40 and 60 cm deep.

Wednesday March 15, a few very large natural avalanches (size 3) were observed and reported.These avalanches were located at 1800 meters on north to north east aspects and had deep crowns, estimated at 1.5 to 2 meters. The avalanches failed on the mid February crust during the warming period, and initiated at the top of steep convex rolls, with unsupported terrain below.

Thursday March 16, Skiing cutting late in the day at treeline on a northwest aspect, produced small (size 1) wind slabs just below ridge top, being very touchy and running on the melt freeze crust, These avalanches did not have enough mass to run far

Snowpack Description: New low density snow of up to 15cm is bonding poorly to a very hard surface crust that formed on all aspects and elevations below 1800 meters. The hard crust has bridged the snow pack and boots or skis in most areas would not penetrate it.  Moderate south east and south west wind has transported this new snow to lee aspects. The persistent weakness can be found down 80 to 100cm and up to 200cm in lee areas in the alpine. Below is a well settled snow pack

Surface- new low density snow of up to 15cm overlie a well developed melt freeze crust approx 15cm in depth

Upper-   80 to 100cm overlie the persistent melt freeze crust

Mid-    Well settled.

Lower-Well settled.

Weather Forecast:

 A westerly flow will continue to bring moderate south east and south west wind with moderate snowfall. Temperatures are expected to remain cool with freezing levels staying below 1000 meters for the duration of the forecast period

Friday -    up to 10 cm new snow   Winds SE to 30 km/hr Freezing level 700 to 900 m.

Saturday- up to 10 cm new snow  Winds SW to 25 km/hr Freezing level 700 to 900 m.

Sunday-  up to 5 cm new snow  Winds SW to 15 km/hr  Freezing level 0 to 900 m. 

Prepared by Jesse Percival

This Bulletin Valid Until: Wednesday March 15, 2017 6 pm. 

​

Confidence: Moderate 

Main Concerns: (Avalanche problems)

Loose Wet-   Continued warm temperatures and rain will break upper snow pack cohesiveness creating loose wet avalanches at all elevations and on all aspects.Human trigger avalanches are near certain and natural avalanches will be very likely. Expect avalanches from loose wet to be small in size in many areas and could large in specific areas if loose snow wet snow can gain enough volume as it slides.These avalanches will be most prevalent in steep rocky thin areas and small loose wet avalanches could push skiers over hazards within terrain. Be aware of all hazards both above and below. 

Wind Slab-   Touchy to very touchy wind slabs will be found in the alpine and at treeline. Continued warm temperatures and rain will add load to these wind slabs, human trigger avalanches are near certain and natural avalanches will be very likely. Expect avalanches from wind slab to be large in size in many areas and very large in specific areas. 

Storm Slab-  Up to 90 mm of rain during this forecast period will increase the sensitivity of the current storm slabs on all aspects and at all elevations. Natural avalanches are very likely and human trigger avalanches are near certain. Expect avalanches from storm slab to be large in many areas and very large in specific areas.

Cornice-   Past wind and precipitation has formed new fragile cornices at ridge top in the alpine and at tree line. Cornices will almost certainly fail and fall as load increases with rain and as upper snow begins to lose cohesiveness during the warming event. Cornice failures may trigger any of the noted avalanches problems. Give these features a wide berth and be aware of overhead local terrain features that promote cornice formation. 

Persistent Slab-  This persistent weakness within the snow pack and is bonding moderately well and can be found down 100 to 150 cm.  Forecast loading in the form of rain and warming may wake this deep instability. Human trigger and natural avalanches are possible and could produce very large avalanches in specific terrain.

Travel/Terrain Advice:  Very dangerous avalanche conditions, travel in avalanche terrain is not recommended. If users intended to travel in avalanche terrain make conservative decisions. Choose simple or non avalanche terrain that is well supported and low angle terrain. Be especially aware of over head hazards.

Past Weather: Up to 15 cm of snowfall and rain in the last 72 hours with moderate Se and Sw wind. Temperatures and freezing levels slowly rose, with Sunday being he warmest day.

Avalanche Summary:  Numerous small ( size 1)  wind slab and storm slab avalanches where triggered on N and Nw aspects using explosives. Crowns down up to 60cm in wind loaded zones. Mid and North island zones reported skier trigger large avalanches on west aspects (size 2). All running on interface between old and new snowfall

Snowpack Description: 

Surface- moist and wet depedant on elevation

Upper-  100 to 150 cm overlie a melt freeze crust

Mid-    Well settled.

Lower-Well settled.

Weather Forecast:

  A south westerly flow will bring to the area moderate precipitation and wind. Freezing  levels and temperatures will remain high. Western coastal areas in the forecast region will receive the strongest winds and the highest amounts of precipitation. Beginning mid day Wednesday, freezing levels will begin to drop and precipitation in the alpine and tree line will begin to fall in the form of snow.

Mon - up to 20mm of rain   Winds SE to 75 km/hr Freezing level 1500 to 2000 m.

Tues- up to 50mm of rain  Winds S to 50 km/hr Freezing level 1500 to 1600 m.

Wed- up to 16mm of rain  Winds SW to 40 km/hr Freezing level 1500 down to 400 m. 

Prepared by Jesse Percival