22-23

Mount Abundance

Cooke City

4/2/2023

Code

HS-N-R4-D3.5

Elevation

9800

Aspect

Latitude

45.06720

Longitude

-110.01600

Notes

Documenting local avalanche cycles, attached is a photo of an avalanche on the south face of Mt. Abundance taken yesterday, that likely happened last Sunday (?) when we got 1" of SWE overnight. Lots of debris chunks the size of refrigerators. Crown mostly covered by wind blown snow.

Number of slides

Number caught

Number buried

Avalanche Type

Hard slab avalanche

Trigger

Natural trigger

R size

D size

3.5

Problem Type

Persistent Weak Layer

Read more about Deep Slab Avalanche on Mt. Abundance

Slab Thickness

60.0 inches

Vertical Fall

750ft

Slab Width

600.00ft

Images

Huge deep slab on Mt. Abundance

Snow Observation Source

Deep Slab Avalanche in Mt. Abundance

Slab Thickness units

inches

Single / Multiple / Red Flag

Single Avalanche

Advisory Year

22-23

Deep Slab Avalanche in Mt. Abundance

Date

Sat, 04/08/2023 - 13:55

Activity

Skiing

Region

Cooke City

Location (from list)

Mount Abundance

Observer Name

Beau Fredlund

Warm Temperatures, Wet Snow in Hyalite

Date

Sun, 04/09/2023 - 13:15

Activity

Skiing

We toured in Hyalite today. By 10:30 in the morning we saw wet, natural avalanches coming down east facing cliffs. We also saw several pinwheels from yesterday. By noon we were at 9,900' on a SE facing aspect, and the snow surface was wet at this altitude. Once we were down at 9,000' the top 8" of snow was wet, and it was beginning to move as a slab on small rollovers.

Region

Northern Gallatin

Location (from list)

Flanders Creek

Observer Name

Dave Zinn, Alex Haddad

Northern Bridgers Avalanche

Date

Sun, 04/09/2023 - 15:29

Big Unit of a avalanche, photo taken from the Seitz road.

Region

Bridger Range

Observer Name

Paul Puettmann

Large avalanche in Taylor-Hilgard

Koch Peak

Southern Madison

4/2/2023

Code

HS-N-R3-D3

Aspect Range

N-NE

Latitude

45.03670

Longitude

-111.45900

Notes

From an email:

We rode back to the wilderness boundary in Bear Creek on Buck Ridge today. The riding was pretty good; new snow from earlier in the week had some wind effect but there were very few hard wind slabs to be found (maybe on the highest most exposed ridges). The day started calm but the wind picked up after noon. We didn’t notice any freshly drifting snow but some of the southern exposures were getting a little wet.

We didn’t see any recent avalanches in the terrain on or immediately around Buck, however we did spot 1 medium and one older, large avalanche in the Taylor-Hilgard range. The northern most one was smaller and was a pocket just below a ridgetop that appeared to be very wind loaded. The other appeared to be an entire basin that had slid, the crown was visible around the upper third of the bowl and there was a large, coarse debris pile in the bottom. This one was east of Koch Peak, above tumbledown creek. Couldn’t get a good picture of either but could see through binoculars pretty well. Aspect on both was N/ NE and both slid before the snow earlier this week, hard to say when.

(estimated 4/02, GNFAC)

Number caught

Number buried

Avalanche Type

Hard slab avalanche

Trigger

Natural trigger

R size

D size

Problem Type

Persistent Weak Layer

Read more about Large avalanche in Taylor-Hilgard

Snow Observation Source

Large avalanche in Taylor-Hilgard

Slab Thickness units

centimeters

Single / Multiple / Red Flag

Multiple Avalanches

Advisory Year

22-23

Large avalanche in Taylor-Hilgard

Date

Sun, 04/02/2023 - 07:05

Activity

Snowmobiling

From an email:

(estimated 4/02, GNFAC)

Region

Southern Madison

Location (from list)

Koch Peak

Observer Name

Kyle Marvinney

GNFAC Avalanche Forecast for Sun Apr 9, 2023

Snowpack and Avalanche Discussion

Temperatures will rise to at least 5 degrees warmer than yesterday, increasing the chances for wet snow avalanches. Additionally, a person can trigger avalanches that break on buried persistent weak layers. These could be 1-2 feet deep below last weekend’s snowfall or several feet deep on weak layers buried in January. If that isn’t enough to worry about, warm temperatures and sunshine might cause cornices to break off ridgelines which could trigger larger avalanches on slopes below.

An extensive and diverse list of avalanche activity over the last week shows what is possible today:

<ul>
<li>Yesterday near Quake Lake a large natural wet avalanche buried the highway (<a href="https://www.mtavalanche.com/node/29022"><span… and details</a>). </li>
<li>On Thursday, near Cooke City a skier triggered a wind slab on Scotch Bonnet Mountain (<a href="https://www.mtavalanche.com/node/28986"><span… and photo</a>), and in the northern Gallatin Range a snowmobiler triggered a 1 foot deep wind slab (<a href="http://www.mtavalanche.com/node/28998">… and photos</a>). Natural avalanches also broke 1-3 ft deep on wind-loaded slopes near Cooke City (<a href="https://www.mtavalanche.com/node/28994"><span… details 1</a>, <a href="https://www.mtavalanche.com/node/29005"><span… details 2</a>) and in the <a href="https://www.mtavalanche.com/node/28983"><span… Range</a>. These likely broke on weak layers below last week’s snowfall.</li>
<li>After last weekend’s storm multiple huge avalanches broke several feet deep on weak layers that were buried months ago. <a href="https://www.mtavalanche.com/images/23/huge-deep-slab-mt-abundance"><spa… massive slide on Mt. Abundance near Cooke City</a> that was not previously reported is a good example, and there were deep slabs early last week in the <a href="https://www.mtavalanche.com/node/29012"><span… Madison Range</a>, <a href="https://www.mtavalanche.com/node/29004"><span… Gallatin Range</a>, near <a href="https://www.mtavalanche.com/node/28949"><span…;, <a href="https://www.mtavalanche.com/node/28924"><span… City</a>, and in the <a href="https://www.mtavalanche.com/node/28900"><span… Range</a>.</li>
</ul>

Warm temperatures the last couple days began to melt the upper layers of the snowpack on lower elevation slopes and slopes that receive direct sunshine. Last night, below freezing temperatures and clear skies re-froze the snow surface making it strong this morning, but this crust will not last long with today’s sun and heat. The crust will melt and make wet snow avalanches easy to trigger this afternoon, these could be large and a few may release naturally. Anticipate wet slides when the upper few inches of the snowpack become soft and wet, indicated by sinking above your ankles in wet snow. Be alert for quickly changing conditions and plan to be off and out from underneath steep slopes before the top few inches of snow become wet.

Before riding any steep slopes, dig down a couple feet to investigate for instability below last week’s snow. Deeper buried weak layers are difficult to find and assess, so your best bet is to avoid steep slopes entirely. If you accept the low likelihood, high consequence risk and venture into steep terrain, choose slopes without previous wind-loading and without consequences like trees, cliffs or confined gullies.

A variety of avalanche concerns make human triggered avalanches possible. The avalanche danger is MODERATE, and will rise to CONSIDERABLE for wet snow avalanches this afternoon.

We expect wet snow avalanche danger will increase rapidly over the next couple days with very warm temperatures and no freezing overnight. We will continue to issue danger ratings through Tuesday. Please share avalanche, snowpack or weather observations via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).