22-23

Beehive Basin Prayer Flags

Date
Activity
Skiing

Our party toured up to Prayer Flags this morning. We found 10-15 cm of low density new snow drifted much deeper in some places. Their were moderate winds out of the west to north. We stomped small soft slabs of wind drifted snow at the ridge breaking 10-15 cm deep and only 5-10 feet wide at the new/old interface. We also witnessed small point releases on very steep slopes and around cliffs triggered by spin drifts. We Found cracking in the new snow on both East and West sides of the ridge between Beehive and Middle. On unprotected solar aspects you could feel a sun crust under the new snow. Places unaffected by the sun were bottomless feeling. We had no note worthy results in our quick test pit.

Region
Northern Madison
Location (from list)
Beehive Basin
Observer Name
Jackson

Natural avalanche in Red Canyon

Date
Activity
Snowmobiling

Seemed to be a decent sized slide runoff was pretty deep where it stopped in the trees figured it was probably two days old. Southwest facing. Roughly 44.86695° N, 111.24123° W

Location (from list)
Red Canyon

GNFAC Avalanche Forecast for Sun Feb 19, 2023

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>In the Bridger Range, 20” of new snow (1.2” snow water equivalent (SWE)) and increasing west wind creates very dangerous avalanche conditions on wind-loaded slopes. Human-triggered and natural avalanches are likely, especially where the new snow is drifted into thicker slabs. Avalanches of new and wind-drifted snow will be large enough to bury a person, and there is a chance larger avalanches will break deeper on older buried weak layers. Avoid travel on and underneath steep, wind-loaded slopes. Conservative decision making and cautious route finding are essential today. With wind expected to increase and a few more inches of snow, stability will get worse. Avalanche danger is HIGH on wind-loaded slopes and CONSIDERABLE otherwise.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>In the northern Gallatin Range, moderate to strong wind will drift 8” of new snow (0.6” SWE) into denser, thick wind slabs that are easy for a person to trigger. On wind-loaded slopes, human triggered avalanches are likely and could be large enough to bury or injure a person. On non-wind loaded slopes avalanches could break below the new snow, possibly on weak layers buried 2-3 feet deep. Be extra cautious of wind-loaded slopes, and carefully assess the stability of new snow and buried weak layers before riding or crossing any steep slope. Avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on non-wind loaded slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>In the Madison Range and southern Gallatin Range 5-10” of low-density snow (0.2-0.4” SWE) creates heightened avalanche conditions. A person can trigger a slab of freshly drifted snow which may be large enough to bury you, but even a small drift can be dangerous if it carries you into a terrain trap like trees or over a cliff. The weight of fresh drifts may cause avalanches to break deeper and wider on weak layers buried 1-3 feet deep. Before riding steep slopes, carefully evaluate the snowpack for fresh drifts and buried weak layers. Avalanche danger is MODERATE.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Near Cooke City and West Yellowstone, a person can trigger avalanches that break in recently formed drifts of snow, or fresh drifts that form as snow falls later today (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/snowmobiler-triggered-avalanche-l…;). Recent wind out of the north and west drifted snow into thicker slabs, and two days ago, riders north of Cooke City saw a recent snowmobile triggered slide on Crown Butte (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28183"><span><span><span><strong><span…;). Today, new snow will be drifted into fresh slabs that can be triggered by a skier or rider. Before riding steep slopes, carefully evaluate the stability of recently formed drifts. Avalanches on weak layers buried 1-3 feet are currently unlikely, but it is worthwhile to dig to assess these weak layers before riding steep slopes (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=fxaqxUH9umA"><span><span><span><strong>… video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Avalanche danger is MODERATE on wind-loaded slopes and LOW on non-wind loaded slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Expect avalanche danger to rise overnight and tomorrow. If heavy snowfall begins early today, fresh unstable drifts may form and cause danger to increase by this evening.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs).</span></span></span></span></span></span></p>

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.

Pit Results and Wind Loading

Date
Activity
Skiing

Dug a quick pit on a west aspect on the west side of Woody Ridge. HS was 178 cm. ECTN 29, 1.5’ below surface on 1.0 mm rounding facets. Skied off the west side of the ridge. The snow was more wind drifted towards the bottom of our run, 4-6” wind skin in spots. We didn’t see any signs of avalanche activity. Snow started falling lightly around 1400.

Region
Cooke City
Location (from list)
Woody Ridge
Observer Name
Alex Haddad

Mt. Ellis

Date
Activity
Skiing

Went for a quick tour up Ellis today. Dug twice along the ridge, both pits had ECTN 12-14 under the new snow. Top of Ellis was worked by the east winds. Worked my way down carefully on the southern end of the Meadow area. Overall the stability seems to have improved since Doug and Ian were up earlier in the week.
 

Region
Northern Gallatin
Location (from list)
Mt Ellis
Observer Name
Karl Birkeland

Fairy lake wind slabs

Fairy Lake
Bridger Range
Code
SS-ASc-R1-D1-I
Elevation
8000
Aspect
SW
Latitude
45.91260
Longitude
-110.95500
Notes

Triggered a couple small slides on the cornices that typically form in the corridor here: 45.91263, -110.95506

wind was blowing in strong gusts and it started snowing very heavy around 1pm  

super reactive. Approached the small slope and the whole thing went. It was only 2-3 inches deep. Likely from wind blown today and some of what was falling. It did run for about 40-50 wide. Nothing that would bury a person but definitely a telling sign. 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
1
D size
1
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
3.0 inches
Slab Width
45.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Encouraging test scores in Beehive Basin

Date
Activity
Skiing

My group and I went up into Beehive Basin to do some sub-alpine skiing into Middle Basin as well on some of the east aspects in Beehive. We went in feeling good about the snowpack given recent observations and the forecast, but before dropping into our first line on the Middle/Beehive ridgeline we dug a pit on an E aspect at around 9500'. There was good depth in the area (HS 190 cm) and the upper few feet of the snowpack was mostly right side up with faceted snow towards the bottom that appeared to be gaining strength. We pulled a shovel shear, which yielded unremarkable results and an ECT with a result of ECTX. We had a great day out there skiing and felt good about what we saw!

Region
Northern Madison
Location (from list)
Beehive Basin
Observer Name
Eric Heiman

Fairy lake wind slabs

Date
Activity
Skiing

Triggered a couple small slides on the cornices that typically form in the corridor here: 45.91263, -110.95506

wind was blowing in strong gusts and it started snowing very heavy around 1pm  

super reactive. Approved the small slope and the whole thing went. It was only 2-3 inches deep. Likely from wind blown today and some of what was falling. It did run for about 40-50 wide. Nothing that would bury a person but definitely a telling sign. 

Region
Bridger Range
Location (from list)
Fairy Lake
Observer Name
Christian Schumacher

Many large Natural Avalanches at Lionhead

Lionhead Ridge
Lionhead Range
Code
HS-N-R2-D2-U
Elevation
9200
Aspect Range
E, NE, N
Latitude
44.71450
Longitude
-111.31800
Notes

As we rode into Lionhead we saw many slides that either ran naturally or from cornice falls. Most of the slides happened Fri or Sat. Winds are blowing strong at all aspects and elevations. Slopes are being loaded further and we triggered a small slide (video) from 50 feet away (aka remotely triggered)(separate avy log record). This is a serious sign of instability and we were careful to not get on or underneath avalanche terrain.

On Feb 11 we saw evidence of widespread activity that likely occurred during this cycle on 1/29-1/30.

Number of slides
10
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
U - Unknown
Problem Type
New Snow
Slab Thickness
18.0 inches
Vertical Fall
700ft
Slab Width
200.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year