Current avalanche advisory for: Arthur's Pass
Issued at 7/08/2016 6:48pm. Valid till 10/08/2016 6pm
High Alpine
Above 2000 meters
Alpine
1000 to 2000 meters
Sub Alpine
Below 1000 meters
Primary Avalanche Danger
Dangerous Aspects
Likelihood
Certain
Size
Largest
Likley
Unlikely
2
Trend
Time of day
Increasing
No change
Small
Decreasing
11am - 5pm
Description:
When the sun comes out for the next few days it
will have a drastic affect on the top layers of the
snow. Be mindful that there has been a lot of
new snow over the past 10 days that has only
seen one day of sun. Watch for pinwheels as a
pre-indicator for wet loose slides. These can be
small, but still have plenty of force to push a
backcountry traveler over or into a terrain trap.
High Alpine: Above 2000m
Alpine: 1000 to 2000m
Low Alpine: Below 1000m
Highest Danger Rating
Secondary Avalanche Danger
Dangerous Aspects
Likelihood
Certain
Size
Largest
Likley
Unlikely
2
Trend
Time of day
Increasing
No change
Small
Decreasing
All day
High Alpine: Above 2000m
Alpine: 1000 to 2000m
Low Alpine: Below 1000m
Highest Danger Rating
Description:
Old weak layers have been dormant and
unreactive for a while but new loading could
awaken these sleeping dragons. These weak
layers are anywhere from 70-200cm down. Be
cautious on all avalanche terrain in S-E aspects
above 1500m. If this layer continues to be
dormant it may have rounded (stabilized)
enough to not be of concern. Size 3 avalanches
have been observed near Cook, running on
these old layers - stay CAUTIOUS!
Tertiary Avalanche Danger
Dangerous Aspects
Likelihood
Certain
Size
Largest
Likley
Unlikely
2
Highest Danger Rating
Trend
Time of day
Increasing
No change
Small
Decreasing
All day
Description:
There are two different types of wind slab
problems: recent light snowfall with only
moderate-strong winds have not produced
sizeable new avalanches but have rather
compacted and stiffened older slabs. There are
small soft slabs lee to the S; and stiff, thick, and
stubborn wind slabs on the Southerly half.
These new layers will gain strength into and
through the week.
High Alpine: Above 2000m
Alpine: 1000 to 2000m
Low Alpine: Below 1000m
Current Snowpack Conditions
There is snow all the way down to the AP visitor's center, and Goat Pass Hut. Most Temple Basin visitors are skinning up and riding back down all
the way to the carpark. The last week's snow is bonding well to lower layers and the prominent July 23 rain event is playing nicely and not
producing facets at the moment. On the Surface there is a funky combination of sun affected (Northerly) or wind hammered (Southerly) snow.
Deeper in the snowpack on S-E, shady, slopes there are still lingering weak layers. These problem (facet and significant graupel) layers have
been quiet but they are still out there (from 50-300cm deep).
Recent Avalanche Activity
Over the weekend there were several fast small dry loose avalanches on W-N aspects and only one observed wind slab avalanche in a Northerly
chute. Sunday's afternoon solar gain produced roller balls but no wet slides that I know of.
Mountain Weather
Monday continues Sunday's pattern of sunny but cool days (thanks to Southerly winds), possibly until Thursday/Friday.
For more information go to: http://www.metservice.com/mountain/index
Sliding Danger
Beware of melt freeze and, or, rain crusts. Particularly in the mornings on Northerly aspects there is a significant sliding hazard. Crampons and Ice
Axe are strongly recommended.
Forecast by Peter Biskind