Dec 25 Avalanche Report - worser....LOL
Dave Ward
Avalanche Forecast
Date/Time Issued: December 24, 2005 at 1600
Valid Until: December 26, 2005
You can help us improve our forecast by posting observations on our website
in the "Discussion" area, sending us an email at forec...@avalanche.ca, or
calling us at 250-837-2435.
Northwest Region Avalanche Forecast
Forecast Area: This forecast includes northwest BC coastal and inland areas
in the Coast, Skeena and Hazelton Mountain ranges. This region includes the
Coast Mountains east of Prince Rupert, north of Kitimat and east of Stewart,
the Skeena Mountains from Ningunsaw Pass in the north to New Hazelton in the
south, and the Hazelton Mountains between Terrace and Smithers.
Forecast of avalanche danger beginning Saturday, December 24, 2005:
Day:\Saturday p.m.\Sunday\Monday
Alpine:\Moderate\Moderate\Considerable
Treeline:\Moderate\Moderate\Considerable
Below Treeline:\Low\Low\Low
Travel Advisory: 10 to 15 cm of recent snow with little wind means there was
likely good fun found in the mountains Saturday. Good travel should continue
Sunday, especially when cooling temperatures mean more of the precipitation
will fall as snow and less as rain! As long as new snow amounts are less
than 15 cm a day and the wind remains light, the snowpack should adjust
well. Wind, or deeper than expected new snow amounts will increase the
avalanche danger to Considerable. Increasing winds late Sunday & Monday will
make wind slabs more widespread; winds shifting between the southwest,
south, and outflow easterlies means most aspects will be suspect for slab
development. So, if you're in open areas where the snowpack is dry or
reasonably dry, check for deeper pillows and drifts of wind deposited snow
resting on softer, weaker facets or feathery surface hoar.
Avalanches: No recent reports of avalanches were received.
Snowpack: A widespread layer of large surface hoar buried Dec. 20 is now 15
to 40 cm deep. Inland areas like Ningunsaw reported it as reactive to
triggering. This surface hoar was most prominent in wind-sheltered shady
areas at and below treeline; it's widespread and still on the surface near
Smithers. The fate of this layer under warm conditions near the coast
(places like Terrace) isn't yet known. Near Terrace, 1300 m was the
transition elevation between moist slop and drier snow, so think (and look
for) buried surface hoar above this elevation. Throughout the region, recent
snow rests on a variety of funky layers including sugary facets, surface
hoar, and a variety of thin crusts from mid-December. Near Smithers the
snowpack is reportedly weak, sugary and ready to avalanche whenever a storm
brings in new snow to form a surface slab.
Weather: Up to 15 cm of snow is falling in the region's mountains Christmas
Eve with the forecast calling for precipitation to taper off to very light
amounts Christmas and Monday. Winds should be light from the south &
southwest, increasing late on Christmas and turning to outflow on Monday.
Freezing levels are the most important part of the weather story and they're
falling. Saturday morning they're between 1500 near the coast and 1000 m
inland, but will drop to 1000 m near the coast and right down to the surface
as you move inland.
Issued by: is
South Coast Region Avalanche Forecast
Forecast Area: This forecast includes the southern Coast and northern
Cascade Mountain ranges of BC. This region includes mountain areas in the
Squamish to Pemberton corridor, the eastern Coast range from Lilloet through
the Fraser Canyon to Hope, the Coquihalla and Manning Park areas and
mountain areas adjacent to the Fraser Valley. This forecast region does not
include the Vancouver North Shore Mountains or Vancouver Island.
Forecast of avalanche danger beginning Saturday, December 24, 2005:
Day:\Saturday p.m.\Sunday\Monday
Alpine:\High\High\Considerable
Treeline:\High\High\Considerable
Below Treeline:\Low\Low\Low
Travel Advisory: Warm temperatures, strong winds, the added weight of new
snow, and the injection of warm rain (to mountain top) combined to create an
avalanche cycle on all aspects Saturday. Highest danger will remain on all
aspects at higher elevations where the recent snow was able to accumulate.
Falling temperatures on Sunday will help strengthen the new snow, but this
will take some time so don't expect an immediate improvement when the
visibility improves and a crust starts to form. If you're brave enough to
head for the hills heed signs of avalanche danger like recent avalanche
activity, whumpfs, and shooting cracks. Test small slopes and be prepared to
stay on smaller gentler slopes. If you're keeping to trees for visual
reference; remain aware of the possibility of avalanches coming down from
slopes & start zones hidden in clouds above.
Avalanches: Field reports are confined to the Whistler area where a natural
avalanche cycle is underway. Many avalanches are wet slabs and loose snow
big enough to bury a person; however, some larger size 2.5 avalanches with
100 cm thick crowns were spied through the fog and blowing rain / snow.
Snowpack: At lower elevations the snowpack is shrinking and isn't deep
enough to cause much avalanche danger-any loose wet avalanches are likely to
be small. Recent storm snow is warm, moist, and now extends to mountain top.
In fact, on Saturday it's been raining to mountaintop. Snow accumulations
could be as much as 100 cm at high elevations along the outer coast
mountains, like near Whistler. Below the recent snow it's likely that the
weaker sugary layers, surface hoar, and crusts are disappearing. However, at
cooler high elevation sites it's possible that below the moist cap the snow
remains colder, drier and layered. If this is the case, the cap of firm snow
covers surface hoar, thin crusts, and sugary layers of facets-all weak
layers.
Weather: Warm, wet, southwest winds continue to hit the coast Saturday with
freezing levels near mountaintop and strong southerly winds. The outer coast
(North Shore Mtns, Whistler) continue to be hosed while inland areas are
received much less precipitation. Cooling is expected Christmas as freezing
levels drop from mountain top (2500 m) to 1200 - 1500 m by Sunday evening.
Sunday will also be drier with only light precipitation in most areas. Warm
storms are forecast to continue, hitting the coast daily through Wednesday.
Issued by: is
North Columbia Region Avalanche Forecast
Forecast Area: This forecast includes the north part of the Monashee,
Cariboo and Selkirk Ranges of the Columbia Mountains. This region includes
areas north & east of Kamloops east of the Fraser Plateau north to Prince
George, the Cariboos & Selkirks west of the Rocky Mountain trench between
McBride & Golden and areas north of Hwy 1 between Kamloops & Golden.This
forecast region does not include Glacier National Park.
Forecast of avalanche danger beginning Saturday, December 24, 2005:
Day:\Saturday p.m.\Sunday\Monday
Alpine:\High\High\Considerable
Treeline:\High\High\Considerable
Below Treeline:\Moderate\Moderate\Moderate
Travel Advisory: The snowpack has dangerous layering with cohesive surface
slabs up to 60 cm thick over weak layers. Weak layers will continue to be
loaded by additional snow (and rain) Sunday. Precipitation needs to end and
temperatures cool significantly before the avalanche danger will improve.
Until this happens, a high level of caution and expert avalanche skills are
required to safely travel in the mountains. If you're keeping to trees for
visual reference; remain aware of the possibility of avalanches coming down
from slopes & start zones hidden in clouds above. Also be aware that large
avalanches starting on slopes high above you could travel all the way to the
valley floor.
Avalanches: Natural avalanches as large as size 3.5 released on Friday and
Saturday. Equally important are reports of remotely triggered avalanches
from as far as 80 m away. These remote triggers show how easily a fracture
can propagate along the weak layer. Slope cuts by professionals on small
steep unsupported rolls consistently triggered avalanches. All aspects are
similarly affected and suspect.
Snowpack: Recent snow since Dec 20th has put 25 to 60 cm slab of warm
cohesive snow above a well developed layer of surface hoar (5-20 mm) and a
20 to 25 cm thick layer of weak sugary facets. Easy stability test results
are reported on these weak layers below the recent firm snow. More
importantly, this weak interface is releasing avalanches naturally, by
remote triggers, and direct human triggers. Further down in the snowpack are
two other surface hoar layers. The more notable of these, the November 25
layer, sits on top of a crust. The deeper layers are noteworthy because
small slides could step down to become bigger avalanches.
Weather: Warm temperatures, light to moderate southerly and southwest winds,
and precipitation in the form of both rain and snow continue Saturday.
Unfortunately rising freezing levels to near 2500 m Saturday (night) mean
rain is creeping higher and higher toward mountain top. Sunday will be
cooler with freezing level forecast to drop to 1200 - 1500 m. A Christmas
day disturbance is expected to bring another 10 cm of snow to southern areas
in the region like Revelstoke, and as far north as Williams Lake, Blue
River, and Mica Creek. More snowy systems are forecast for Monday, Tuesday,
and Wednesday!
Issued by: is
South Columbia Region Avalanche Forecast
Forecast Area: This forecast includes the southern Columbia Mountains,
including the Monashee, Selkirk and Purcell Mountain ranges. This region
includes the eastern side of the Okanagan Valley from Osoyoos to Enderby,
areas south of Highway 1 from Sicamous to Golden, areas west of the Columbia
River between Golden & Kimberley, and areas north of Kaslo and Castlegar.
This forecast region does not include Glacier National Park.
Forecast of avalanche danger beginning Saturday, December 24, 2005:
Day:\Saturday p.m.\Sunday\Monday
Alpine:\High\High*\Considerable
Treeline:\High\High*\Considerable
Below Treeline:\Moderate\Moderate\Moderate
Travel Advisory: *High danger applies to the deeper snowpack areas of the
Monashee and Selkirk Mountains. Shallower snowpack areas in the Purcells
that received less recent storm snow will remain at Considerable danger. If
you're planning a trip to the mountains for the Christmas holiday, you're
advised to watch the weather closely and pay attention to Mother Nature's
signs of unstable snow (i.e. avalanches). The snowpack is undergoing a
transformation due to the additional weight of snow and rain, and this will
be compounded by warming above zero degrees to mountain top Christmas Eve.
Once the precipitation abates and significant cooling occurs, then avalanche
danger will start to drop. Until this occurs, a high degree of caution and
skill will be required to travel safely in the backcountry.
Avalanches: Reports of natural avalanches were more limited than in
surrounding regions, but several skier controlled avalanches were triggered
in the storm snow and underlying weak facets, 30-50 cm deep. With slabs this
deep, the size potential of avalanches has increased to the point where they
could bury a person.
Snowpack: Snowfall continued to load the snowpack with 10-20 cm of snow on
Friday to Saturday, and this will change to rain to about 2500 m on
Christmas Eve. There is now 20-50 cm of denser recent storm snow overlying a
very weak combination of surface hoar, faceted crystals and crusts. Reports
from the Bugaboos area describe extensive cracking and whumpfing (settlement
sounds) in the storm snow. Other areas in the Purcells report that only wind
and warm temperatures are required to turn good powder into a slab over weak
snow. Significant variation exists in the region, with higher instability in
areas that received greater snowfall.
Weather: Up to 10 mm of precipitation fell Friday and another 5-15 mm fell
Saturday, accompanied by near zero temperatures around 1800 m. Temperatures
are rising late Saturday and the freezing level is expected to rise to 2500
m by Christmas Eve and stay high overnight, finally dropping to 1500 m
midday Sunday. Winds are just starting to pick up late Saturday from the
southwest, and should peak at around 50 km/hr overnight before easing off to
20-30 km/hr Sunday. Expect continuing snowfall of 5-15 cm above 1500 m on
Sunday, then light flurries and cooler temperatures for Monday.
Issued by: aj
Kootenay Boundary Region Avalanche Forecast
Forecast Area: This forecast includes the southern edge of the Columbia
Mountains bordering the US/Canada border, including parts of the Monashee,
Selkirk and Purcell Mountain ranges. This region includes mountain areas
east of Greenwood, southeast of Castlegar, the Selkirk Mountains near
Nelson, Kootenay Pass, and the southern Purcell range west of Kimberley and
Cranbrook to the US border.
Forecast of avalanche danger beginning Saturday, December 24, 2005:
Day:\Saturday p.m.\Sunday\Monday
Alpine:\High\High\Considerable
Treeline:\High\High\Considerable
Below Treeline:\Moderate\Moderate\Moderate
Travel Advisory: If you're planning a trip to the mountains for the
Christmas holiday, you're advised to watch the weather closely and pay
attention to Mother Nature's signs of unstable snow (i.e. avalanches). The
snowpack is undergoing rapid transformation due to the additional weight of
snow and rain, and this will be compounded by warming above zero degrees to
mountain top Christmas Eve. Once the precipitation abates, significant
cooling occurs and a crust forms at the surface, then avalanche danger will
start to drop. Until this occurs, a high degree of caution and skill will be
required to travel safely in the backcountry. Let's hope that some dry snow
sticks after Christmas & we return to the good Kootenay powder we know and
love.
Avalanches: Another natural avalanche cycle is expected to occur overnight
Sunday with continuing precipitation and very warm temperatures almost to
mountain top. Cooling later on Sunday should slow down natural avalanche
activity, but it will likely remain easy for people to trigger avalanches.
Snowpack: A heavy load of rain and snow from Thursday to Saturday has
transformed the snowpack from previous reports. A layer of denser, moist
snow now overlies a mix of weaker, faceted snow and two previously buried
weak surface hoar layers. Warm temperatures have settled this new moist or
wet snow into soft slabs that are reactive to human triggers. Continuing
rainfall up to 2500 m overnight Christmas Eve will continue to wreak havoc
on the snowpack. Consequently, there is little point talking about specific
weak layers until the rain ends, cooling happens, and we can re-assess the
final state of the snowpack.
Weather: Up to 10 mm of precipitation fell Friday and another 5-15 mm fell
Saturday, accompanied by near zero temperatures around 1800 m. Temperatures
are rising late Saturday and the freezing level is expected to rise to 2500
m by Christmas Eve and stay high overnight, finally dropping to 1500 m
midday Sunday. Winds are just starting to pick up late Saturday from the
southwest, and should peak at around 50 km/hr overnight before easing off to
20-30 km/hr Sunday. Expect continuing snowfall of 5-15 cm above 1500 m on
Sunday, then light flurries and cooler temperatures for Monday.
Issued by: aj
South Rockies Region Avalanche Forecast
Forecast Area: This forecast includes mountainous areas in the southeast
corner of BC and the southwest corner of Alberta. It includes mountain areas
in the Elk Valley between Fernie and Elkford, areas east of Canal Flats and
Cranbrook, the Crowsnest Pass, and the east side of the Rocky Mountains
south of Kananaskis Country. The region does not include Kananaskis Country
or Kootenay and Waterton Lakes National Parks.
Forecast of avalanche danger beginning Saturday, December 24, 2005:
Day:\Saturday p.m.\Sunday\Monday
Alpine:\Considerable\High\High
Treeline:\Considerable\High\High
Below Treeline:\Low\Low\Low
Travel Advisory: Get set for another blast of moisture on Sunday as the next
Pacific system works it way to the Fernie area. For travelling in the
backcountry this will mean high avalanche danger at treeline and above by
Sunday as the weak underlying layers are significantly stressed with new
snow. A cycle of natural avalanches is almost certain for Sunday, and it is
also likely that avalanches could be triggered by sledders or skiers in the
alpine or at treeline at any time over the next couple of days. Unless
significant cooling occurs on Monday to form a thick supportive crust at the
surface, then avalanche danger will remain elevated. Avalanche danger east
of Crowsnest Pass is generally lower since little snow/rain will make it
past the divide.
Avalanches: Avalanches continued to occur around Fernie Friday, with several
large (Size 2.5-3) natural and explosive triggered avalanches reported.
Another period of avalanche activity will occur Sunday, but more importantly
it is likely that avalanches could be triggered by people on moderately
angled terrain. Avalanches are also expected Monday, but activity should
subside as the mountains start to cool.
Snowpack: The snowpack continues to change with the rapid loading of snow on
top of a weak combination of facets, crusts and surface hoar layers. There
is little point talking about specific weak layers until the rain ends,
cooling happens, and we can re-assess the final state of the snowpack. East
of the divide things are different as Chinook conditions are causing the
snowpack to settle and slowly disappear. Below treeline the snowpack is
saturated and may be isothermal, but also mostly too thin to be a concern
for avalanches.
Weather: Very warm and wet weather will continue in the Fernie area, while
the Crowsnest and areas east will continue to have warm Chinook weather with
little precipitation. The next wave of moisture will begin Christmas Eve and
will bring above zero temperatures into the alpine again. We can expect to
see precipitation amounts of 20-40 mm in the Fernie area through Sunday;
this will bring 20-40 cm of snow to alpine areas above 2000 m, but only
misery to lower elevations at first before cooling starts Monday morning.
Winds will be moderate to strong from the southwest with the storm.
Issued by: aj
Important Notice:
This is a regional forecast and significant variation may exist within the
forecast area. The information and danger ratings are intended as a trip
planning aid for recreational, backcountry users of avalanche terrain; they
are not meant to be used as the sole factor in determining the avalanche
danger presented by a specific slope. Always include local weather, snowpack
and avalanche observations in your decision to travel in avalanche terrain.
Observations and experience may lead to different conclusions from what is
reported or recommended. See disclaimer for further details.
The technical data used to produce these bulletins is obtained from a
variety of sources, including various government agencies and private
companies that participate in an industry-wide daily information exchange
program. These contributors provide data, resources, and funding without
which the Canadian Avalanche Centre could not provide this avalanche
information.
Canadian Avalache Center: