20-21

Mt Blackmore

Date
Activity
Skiing

Skied Mt Blackmore this morning. Skinned up the SE ridgeline and dug a pit at 9700ft on a 25 deg S facing slope. 120cm snow depth, 15cm of new snow on top of a stout ice crust. No unstable stability test results, facets at the ground were moist and 4F. The remainder of the snowpack was very well bonded and almost hard to cut with a snow saw. Did observe a few small crowns that appear to have broken within the new snow on steep terrain across the basin.

Region
Northern Gallatin
Location (from list)
Mt Blackmore
Observer Name
Mike Lavery

Hyalite Reservoir / Meadows south of the reservoir

Date
Activity
Skiing

Was out for a tour at the meadows above Hyalite Reservoir. We were curious about the water affecting the snow pack, dug a pit on a north-west facing aspect around 7800 feet. Snow pack was 135 cm deep, performed a ECT test and got ECTP 11 on the depth hoar at the ground. Stayed off steep slopes and had a fun mellow powder day.

Region
Northern Gallatin
Observer Name
Spencer Lipsteuer

Hyalite Peak

Date
Activity
Skiing

On our way up the summer trail route to Hyalite Peak our party of three remotely triggered a small avalanche from the skin track at around 9,600ft on a east facing aspect. The storm slab went about 4 inches deep and 150-200ft across a small roll over feature. We were about 150ft away when we triggered the slide. This dramatically altered our tour plan, but we still stepped out into some avalanche terrain later in the day. By mid-morning it was quite hot up high and much of the new snow had consolidated into a few inches of heavy slop that was much less excited to move. I’ve attached a picture but it’s quite cloudy and I didn’t have anything in frame for reference... so maybe not very helpful.

Region
Northern Gallatin
Location (from list)
Hyalite Peak
Observer Name
Chris Kussmaul

West of Sawtelle Peak

Date
Activity
Snowmobiling

Surface was boiler plate leaving Island Park. We rode up high to the ridge (9200’) to the west of Sawtelle Peak and dug on a NE facing slope, 9,200', 6' of snow on the ground. Weak, sugary snow is on the surface (near-surface facet) and the main issue with the new snow. The new snow won't stick to the old surface and avalanches will be likely. Sugary depth hoar facets are still felt in the bottom 40 cm but it’s stable for now. Snowpack is very similar to Lionhead. Danger is Low today, but when the new snow arrives through the weekend the avalanche danger will rise.  I imagine it will not bond on many slopes and it will not be obvious where the NSF will be buried.  Tomorrow will be vastly different than today.

Region
Island Park
Location (from list)
Sawtelle Peak
Observer Name
Doug Chabot, GNFAC forecaster

GNFAC Avalanche Forecast for Sat Mar 20, 2021

Snowpack and Avalanche Discussion

<p>The first day of spring feels like a return to winter. This morning there is 6-8” of new snow equal to 0.6-0.8” of snow water equivalent (SWE) near Bozeman, Big Sky and West Yellowstone with steady snowfall expected today. The new snow fell onto weak, sugary snow on some slopes and crusts on other slopes. These interfaces make large avalanches of the new snow easy to trigger and may cause slabs to break wide and run long distances. Yesterday Doug saw the weak snow on the surface in the Centennials (outside our advisory area, but similar snowpack) and explains why it is a concern in his video (<strong><a href="https://www.youtube.com/watch?v=U1b5LjWLTac&amp;list=PLXu5151nmAvQDzKmH…’s video</a></strong>, <strong><a href="https://www.mtavalanche.com/images/21/6-snow-centennials">photo</a></st…;). Doug was snowmobiling with Mark Staples, director of the Utah Avalanche Center, who appears in Doug’s video and discusses terrain to watch out for, such as steep slopes up high and confined gullies where sliding snow can pile up deep.</p>

<p>Carefully assess the stability of the new snow before riding or crossing steep slopes. Expect stability to decrease through the day with continuous snow, and choose simple, less consequential objectives. Today, continued snowfall on top of weak layers and crusts makes human triggered avalanches likely and natural avalanches possible. The avalanche danger is rated CONSIDERABLE.</p>

<p>In the mountains near Cooke City snowfall totals are less than elsewhere, but they should catch up or surpass other places by tomorrow morning. Doug was riding near Cooke City on Tuesday and found weak layers on the surface, similar to elsewhere, that are now buried by new snow (<strong><a href="https://www.youtube.com/watch?v=VQd7lPN6zTQ&amp;list=PLXu5151nmAvQDzKmH…;). This morning a couple inches of new snow will create minimal instability, but this afternoon will be different. Heavy snow today could pile up quickly and create slabs that easily slide on the old snow surface. Expect stability to decrease through the day, and carefully evaluate the stability of the new snow before riding steep slopes. Watch for cracks breaking across the snow surface under your sled or skis as one sign the new snow is becoming&nbsp;unstable. Today avalanches of new snow are possible to trigger and the avalanche danger is MODERATE.</p>

<p>If you get out, please send us your observations no matter how brief. You can submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>website<…;, email (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

Upcoming Avalanche Education and Events

See our education calendar for an up-to-date list of all local classes. Here are a few select upcoming events and opportunities to check out:

TOMORROW! March 20, 5:30 p.m., Snowpack Update for Bozeman Splitfest, online Link to Join HERE

The snowpack in the Centennials is remarkably similar to the Lionhead area outside West Yellowstone: 6 feet of snow at 9,200 feet. The stability will get worse with snow this weekend (19-21 March) because the surface snow is week and the new snow will not bond to it (near-surface facets). Photo: GNFAC


Forecast link: GNFAC Avalanche Forecast for Sat Mar 20, 2021
Island Park, 2021-03-19
Access other image sizes:
  • Very Large 1200px
  • Large 480px
  • Medium 220px
  • Small 150px
  • Original

    • 44.86420, -111.46191

    Date
    Activity
    Skiing

    Started skinning at 8:30 am and snow was firm. On our way up crossed by several small, isolated slides that had initiated at exposed rocks, both east and west aspects. On our route to the summit we experienced no signs to snow instability, the snow pack seemed welded together. Gorgeous day on top and fun ski down, even found some corn snow.

    Region
    Southern Madison
    Observer Name
    David Combs
    Subscribe to 20-21