GNFAC Avalanche Advisory for Sun Mar 31, 2013

Not the Current Forecast

Good morning and happy Easter. This is Eric Knoff with the Gallatin National Forest Avalanche Advisory issued on Sunday, March 31 at 7:30 a.m. Yellowstone Club Community Foundation in partnership with the Friends of the Avalanche Center sponsors today’s advisory. This advisory does not apply to operating ski areas.

Mountain Weather

This morning there is no new snow to report. At 4 a.m. temperatures are in the upper twenties F and winds are blowing 10-20 mph out of the WNW with ridgetop gusts reaching into the 30s. Today will be perfect for Easter activates – skies will be partly cloudy and temperatures will warm into the low to mid-forties F. Winds will continue to blow 10-20 out of the WNW. No precipitation is expected over the next 24 hours. 

Snowpack and Avalanche Discussion

Northern Madison Range  Northern Gallatin Range  Cooke City  

Yesterday, my partner and I toured into Beehive Basin expecting to find 1-3 inches of new snow. This was accurate up to about 9,000 ft., but above that elevation snow totals were around 4-6 inches. Skiers in Hyalite and the Cooke City area found similar conditions. This amount of snow combined with moderate west to northwest winds formed sensitive wind slabs on south facing slopes (photo). These slabs were reactive to ski cuts. The Big Sky and Moonlight Basin Ski Patrols also reported triggering wind slabs up to a foot deep during control work.

Today, pockets of windblown snow will remain sensitive to human triggers. This hazard will be confined to upper elevation slopes on the south half of the compss where wind slabs rest over a stout ice crust. Although relatively small in size, these isolated slabs could push a skier or rider into rocks, gullies or over cliffs. 

As the day heats up, the new snow will provide plenty of ammunition for wet loose avalanches. Obvious clues such a roller balls and small point releases are indicators the surface snow is becoming unstable (photo). If you find the snow surface resembling melted peeps, heading to shadier aspects or home for an Easter egg hunt will be your best option.   

Today, both dry snow and wet snow avalanches are possible and the avalanche danger is rated MODERATE

Bridger Range  Southern Gallatin Range                                          

Southern Madison Range  Lionhead area near West Yellowstone   

These areas did not pick up as much snow, thus there are fewer avalanche problems. Without a dry snow hazard, wet loose avalanches will be the primary avalanche concern. With a solid freeze last night, this problem won’t come into play until late morning-early afternoon. Wet snow activity will start on south facing slopes, but will gradually move around the compass. Avoiding steep, sun exposed slopes later in the day will be the best way to avoid a rotten egg in the basket.

Today, human triggered avalanches are unlikely and the avalanche danger is rate LOW. The wet snow danger could rise to MODERATE on sun exposed slopes by this afternoon.  

I will issue the next advisory tomorrow morning at 7:30 a.m. If you have any snowpack or avalanche observations drop us a line at mtavalanche@gmail.com or call us at 587-6984.

Take Note:

Our 136th and last avalanche advisory will be on Sunday, April 7th

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