Issued: Sat, Apr 07, 2018 at 7AM

Expires: Sun, Apr 08, 2018

Spring is upon us. The last HPAC avalanche advisory of the season will be Sat., April 14th. Keep those observations coming. We will continue to monitor and publish observations throughout the spring season.

Above 3,500ft Low

2,500 to 3,500ft Low

Below 2,500ft Low

Degrees of Avalanche Danger ?

1. Low
2. Moderate
3. Considerable
4. High
5. Extreme

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

BOTTOM LINE

Avalanche conditions are generally safe, and the danger is LOW .  Watch for unstable, wet snow, on isolated terrain features. The hazard for wet avalanches could increase this afternoon and into Sunday if the sun pops out and temperatures reach toward 40°F at 3000′. Avoid steep sunny aspects with direct solar in the afternoon.

 


WET LOOSE AVALANCHE PROBLEM


A
Low Avalanche Hazard exists for Wet-Loose avalanches on steep SE>SW aspects today. Expect sluffs to be D1-D1.5 and small in size. Instability exists in portions of terrain and will be stubborn to trigger.   

 


 

Last week’s snow was magnificent and enjoyed by many at HP.  Although we are currently in a period of generally good stability, identifying and mapping weaknesses in the snowpack is a crucial component to long-term safe travel and riding in avalanche terrain.  Persistent weak layers still exist in the snowpack, but are currently unreactive, and could still be future problems as the snowpack warms up later in the spring.  As temperatures increase, so will avalanche activity. Wet avalanches are predictable and avoidable.  See pit HERE.

Timing is everything. If the surface snow starts to feel like mush, you can squeeze water out of a snowball, and observe roller balls on similar aspects around you- It’s time to get off of and out from under similar slopes.

Check out the Gallatin Nat’l Forest Avalanche center’s video of wet-loose avalanches HERE. This is a similar set-up to Hatcher Pass with weak facets comprising much of the snowpack.

 

Recent Avalanche Activity

A handful of wet-loose sluffs were reported this week.

No slab avalanches were observed or reported this week.

Many bed surfaces from old slab avalanches from the 3/19 cycle are melting out fast.

 

Avalanches from 3/19

Same avalanches as above from 3/19, melting out on 4/6


CONDITIONS

Lasts weeks amazing powder is a little harder to find. Moderate winds this week gusted E 16-33 forming wind slabs 2-6″ thick. Conditions range from wind board, sun crusts, supportable and breakable crusts, faceted powder, and everything in between.

Sun crust on E aspect. Expect to find sun crusts of varying thickness on E>SW aspects.

New thin wind slabs, mostly well bonded, stubborn and unreactive.

 

 

 

 

 

Recent Weather

This week’s weather at 3550′:

Temps averaged 20ºF, with a low of 8ºF and a high of 38ºF.

No new snow this week.

Overnight at 3550′:

Temps averaged 25° F.

No new snow overnight.

This week’s weather at 4500′:

Temps averaged 17ºF, with a low of 3ºF and a high of 31ºF.

Winds averaged E 7 mph, max E 19 mph . Gusts averaged E 12 mph, max gusts E 33 mph.

Overnight at 4500′:

Temps averaged  21ºF overnight.

Winds averaged 5 mph overnight, with a max gust NE 9 mph.


NWS recreational forecast for Hatcher Pass here


NWS point forecast here


State Parks snow report here


NOAA March weather highlights here

Additional Info & Media

Expect the avalanche hazard to remain the same through the weekend. Rising temperatures could increase the avalanche danger for wet avalanches.

NWS is calling for temps 35º at 3000′.  Winds E 0-8 mph.

 

Posted in HPAC Forecasts.
Allie Barker

Forecaster: Allie Barker