Issued: Sat, Mar 31, 2018 at 7AM

Expires: Sun, Apr 01, 2018

Above 3,500ft Moderate

2,500 to 3,500ft Moderate

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

 A Moderate Avalanche Hazard exists for Wet Loose Avalanches today on SW>SE aspects on slopes above 40°.

A Moderate Avalanche Hazard exists for Dry Loose Avalanches today on NW>NE aspects on slopes above 40°.

A Low Avalanche Hazard exists for Persistent Slabs today on all aspects on slopes above 35°.

  


WET LOOSE AVALANCHE PROBLEM

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

Southerly aspects are heating up faster than you think.  Human triggering wet-loose sluffs will be possible this afternoon as slopes heat up.  If you see rollerballs or wet-loose sluffs on similar aspects, it’s time to get off of and out from under steep slopes, find lower angle terrain, and cooler aspects. Expect sluffs to be low to moderate in volume and slow in speed.  Avoiding these avalanches is a manageable risk. Tests and observations are reliable for this avalanche problem.  Timing is key.  Note that some bed surfaces under the new snow are firm sun crusts and may increase the risk for sliding further than you anticipate.


DRY LOOSE AVALANCHE PROBLEM 

A Moderate Avalanche Hazard exists for Dry-Loose avalanches on NW>NE aspects today on slopes above 40°. Expect sluffs to be D1 and small in size. Instability exists in portions of terrain and will be stubborn to trigger. 

Sluff management will be key to avoiding this hazard in steeper terrain where a sluff could knock you off your feet, tweak a knee or carry you into terrain traps. Most natural, loose dry problems are short lived and stabilize within hours or days. However, as long as the snowpack consists of unconsolidated grains (found with cooler temps on northerly aspects), human triggered loose dry sluffs will persist. Avoiding loose dry sluffs is a manageable risk.

 

Dry Loose sluffs on steep northerly aspects will be possible today


PERSISTENT SLAB AVALANCHE PROBLEM

A Low Avalanche Hazard exists for Persistent Slab avalanches at all elevations on all aspects, on slopes 35º and steeper.  Instability is spotty and hard to find, and will most likely be unreactive. Expect avalanches to be unlikely to very unlikely to trigger, and up to D2 in size. Low hazard does not mean no hazard. Watch for unstable snow on isolated terrain features. 

This avalanche problem may be in dormancy now, but it has not disappeared.  Stability tests still require a lot of force to get this layer to fail and it is quite deep in many locations. The most likely, isolated, locations for triggering a persistent slab continue to be near rocks and shallow spots in the snowpack. Southerly aspects continue to show the poorest structure, shallower snowpack, and are more likely to resemble this avalanche problem.

Reminders are always good. Our friends at the CAIC say, “The best ways to manage the risk from Persistent Slabs is to make conservative terrain choices. They can be triggered by light loads and weeks after the last storm. The slabs often propagate in surprising and unpredictable ways. This makes this problem difficult to predict and manage and requires a wide safety buffer to handle the uncertainty.” Don’t let the power of powder lend an arm to complacency. This is a good time to continue to practice safe travel protocol.

Weak layer shown more than 3 feet deep here

An old, wise friend once said, “Remember that risk is inherent in mountain travel. One can never diminish it entirely and for some of us this is part of the attraction. The allure. That the outcome is uncertain. But we can travel in appropriate terrain. And strive to understand snow and avalanches. Dial in the rescue protocol. Work to understand our own and our partners’ weaknesses and blind spots.”

 

Recent Avalanche Activity

Several wet-loose and dry-loose sluffs were observed this week, mostly small in size.

No slab avalanches were observed or reported this week.

 

Small wet-loose sluffs were observed on SE>SW aspects this week.

Wet-loose naturals , Divide Ridge, S aspect, 3000′ , 3/30

 

Small to medium size dry loose sluffs were observed on NW>NE aspects this week.

Dry Loose, 3800′ N/NW, 3/30

 

Dry loose on NE and Wet loose on SW triggered on same run. Stairstep spines, 3500′. 3/30

 

 

 

 

 

 

Recent Weather

This week’s weather at 3550′:

Temps averaged 20ºF, with a low of 11ºF and a high of 32ºF.

IM reported about 3-4″ of new snow on 3/28 with .2″ of water (SWE).

Overnight at 3550′:

Temps averaged 17° F.

No new snow overnight.

This week’s weather at 4500′:

Temps averaged 17ºF, with a low of 12ºF and a high of 25ºF.

Winds averaged SE 3 mph, max SE 12 mph . Gusts averaged SE 7 mph, max gusts E>WSW 19 mph.

Overnight at 4500′:

Temps averaged  15ºF overnight.

Winds averaged ENE 3 mph overnight, with a max gust ENE 9 mph.


NWS recreational forecast for Hatcher Pass here


NWS point forecast here


State Parks snow report here

Additional Info & Media

Expect the avalanche hazard to remain the same through the weekend.

NWS is calling for temps 22º at 3000′.  Winds NW 3-7 mph today.


Posted in HPAC Forecasts.
Allie Barker

Forecaster: Allie Barker