This wet loose avalanche is a great example of where they often occur. Rocks absorb extra heat from the sun and can quickly melt and destabilize the snow. Either move under areas like this early in the morning (as we did), or if you have to travel under them later in the day, move quickly.
Trip Planning for Island Park
Primary Problem: Loose Wet
Bottom Line: Today and this weekend, the main threat is wet snow avalanches. A minimal refreeze of the snow this week combined with very warm weather the next few days will increase the odds of wet loose avalanches. Past 5 Days
Sun Apr 20
Low
Low
Mon Apr 21
None
None
Fri Apr 25
None
None
Mon Apr 28
None
None
Fri May 2
None
None
Relevant Photos
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Understanding Avalanche Safety Preparedness – 5-Minute Survey for Motorized Users
We need your input! Eastern Oregon University is conducting a survey to better understand avalanche safety preparedness among motorized backcountry users like you. Your feedback will help us learn more about who is purchasing and practicing with avalanche rescue gear (beacon, probe, shovel) and participating in avalanche education—and why some riders aren’t. The survey is confidential and anonymous.
Your feedback is invaluable in improving avalanche education and awareness. Please take a moment to share your experience and help us make a difference.
https://eoustmhs.qualtrics.com/jfe/form/SV_3L8QKAuZzcxJBLo
Thank you for your time and for being a part of this important effort!
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All elevations in Island Park experienced heavy snowfall combined with high winds,this made for unstable wind slabs and cornices. Photo: K Allred
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We saw a handful of avalanches above treeline terrain that seemed to be wind slabs. However wind and snow had obscured them and I suspect there had been a lot more.
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In the last five days, this area has received snowfall containing 4.5-5.3 inches of water which has settled to about 3 feet of new snow.
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Stability tests continually fractured on old, broken snowflakes just under a crust under the new snow about 16" deep
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Small natural storm slab
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This avalanche started on a slope above the rocks where there was more wind and then triggered another storm slab in the trees. It created a significant debris pile.
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Light red lines indicate crown faces of this natural avalanche. It likely started as a wind slab/storm slab above the rocks, then dropped down onto the slope below triggering a storm slab avalanche that entrained a significant amount of snow and created a big debris pile.
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Two Point release avalanches on south slope of Two Top. 1/30/25. Photo: K. Allred
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Wide spread layer of Surface Hoar mid and upper elevations Two Top area
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Shooting crack in a fresh wind slab near Mt Jefferson
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North facing pit in Hellroaring Creek, Centennials
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North facing snow profile Hellroaring Creek, Centennials
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South facing snowpit Hellroaring creek, Centennials
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S facing snow profile from Hellroaring Creek in Centennials
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The GNFAC weather station at the top of Sawtelle provides wind, temperature and relative humidity information for forecasting (when it's not covered in a foot of rime ice. Photo: GNFAC
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Photo: GNFAC
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From the top of Sawtelle. Photo: GNFAC
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Riders in the Centennial Mountains experienced almost constant whumphing at higher elevation and saw a couple of days old avalanche on a windl-oaded east north east facing slope. Photo: R. Gravett
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Ice crust on trees from freezing rain last Saturday Dec 28 now covered by rime ice.
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From obs on 12/29: "On our way out near the cabin I cut a line close to a creek to see if I could trigger something."
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From obs on 12/29: "On our way out near the cabin I cut a line close to a creek to see if I could trigger something."
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Thick and robust ice crust layer widespread above white elephant. Photo: Ride Rasmussen Style
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Plumes of drifting snow in the Bridger Range as strong winds blasted the mountains. Photo: GNFAC
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De-rimed Sawtell anemometer
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Rock Creek natural avalanche
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NE facing IP snowpit
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E facing IP snowpit
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From IG: On 12/15 "Storm slab broke about 200’ above us as skinning up the hallway coming from the north side on the throne." Photo: Anonymous
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Small windslab triggered on approach for inspection. Failure interface had 5 mm Surface Hoar. Soft slab, remote propagation onto the adjacent slope. Debris covered about half of the road bed.
Photo: J Hambelton
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Small windslab triggered on approach for inspection. Failure interface had 5 mm Surface Hoar. Soft slab, remote propagation onto the adjacent slope. Debris covered about half of the road bed.
Photo: J Hambelton
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Small windslab triggered on approach for inspection. Failure interface had 5 mm Surface Hoar. Soft slab, remote propagation onto the adjacent slope. Debris covered about half of the road bed.
Photo: J Hambelton
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Gusty winds transporting snow in Taylor Fork on Saturday. Triggered a 4-5 inch deep wind slab that propagated about 50 ft at the top of a north east facing slope at 9,500 ft.
Photo: JP
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We are grateful for our partnership with the Friends of the Gallatin National Forest Avalanche Center. It is always a good time to get out in the field with our education coordinator, Shannon. Photo: GNFAC
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The snow depth was 60-70 cm (2-2.5 feet) at the upper elevations of the Big Springs Loop around the Black Canyon area in Island Park. Photo: GNFAC
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Surface hoar and near surface facets are now capped by this weekend's snow. The layers are buried 2-4" deep in the Black Canyon area of Island Park. Photo: GNFAC
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WE facing snow at 8100 ft Cabin Ck
Videos- Island Park
Weather Stations- Island Park
Weather Forecast Island Park
Extended Forecast for10 Miles ESE Lakeview MT
Winter Weather Advisory May 5, 06:00am until May 6, 06:00amClick here for hazard details and duration Winter Weather AdvisoryOvernight
Low: 35 °F
Chance Rain
Monday
High: 39 °F
Breezy.
Chance
Rain/Snow
then
Rain/Snow
LikelyMonday Night
Low: 27 °F
Snow Likely
and BlusteryTuesday
High: 49 °F
Slight Chance
Snow then
Mostly SunnyTuesday Night
Low: 32 °F
Partly Cloudy
Wednesday
High: 55 °F
Sunny
Wednesday Night
Low: 38 °F
Mostly Clear
Thursday
High: 59 °F
Sunny then
Chance
ShowersThursday Night
Low: 39 °F
Slight Chance
Showers then
Mostly Clear
The Last Word
Thank you for another successful season. Our success is directly related to support from our community and the Forest Service. Thanks to the readers of the forecast, everyone that sent in observations, took an avalanche class, or donated money, time or gear. We will issue conditions updates on Mondays and Fridays through April.
GENERAL SPRING SNOWPACK AND TRAVEL ADVICE
Spring weather can be highly variable and create a mix of avalanche problems. Snow conditions and stability can change drastically from day to day or hour to hour. Anticipate rapid change and plan accordingly. Abundant snowfall over the winter with more spring snow to come makes avalanches possible into summer.
NEW SNOW AND WIND LOADED SLOPES
Spring storms are notorious for depositing heavy amounts of snow in the mountains. Even with a deep and generally stable snowpack throughout the advisory area, heavy and rapid loads of new snow will decrease stability. The main problems to look out for are avalanches breaking within the new snow, wind slabs, and loose snow avalanches. The likelihood of triggering an avalanche spikes during and immediately after snowstorms. New snow instabilities tend to stabilize quickly, but it’s a good idea to give fresh snow a day to adjust before hitting big terrain. New snow instabilities can be challenging to assess, and spring storms bond to old snow differently across aspects and elevations. Conservative terrain selection is essential during and immediately following storms. Avoid wind-loaded slopes and slopes steeper than 35 degrees for 24-48 hours after new snow and wind.
New snow can quickly change from dry to wet on a spring day, and stability can decrease rapidly with above freezing temperatures or brief sunshine. New snow may bond well early in the morning and then easily slide later. Wet loose slides are likely during the first above freezing temperatures or sunshine immediately after a storm. Anticipate changes in snow stability as you change aspect or elevation and over the course of the day. An early start is always an advantage. Be ready to change plans or move to safer terrain at the first signs of decreasing stability.
WET SNOW AVALANCHES
Spring and wet snow avalanches go hand-in-hand. Above freezing temperatures, rain, and/or intense sunshine cause the snow to become wet and weak and make wet avalanches easy to trigger or release naturally. Conditions tend to become most unstable when temperatures stay above freezing for multiple days and nights in a row. Avoid steep terrain, and be aware of the potential for natural wet avalanches in steep terrain above you, if you see:
- Heavy rain,
- Above freezing temperatures for more than 24 hours,
- Natural wet avalanches,
- Rollerballs or pinwheels indicating a moist or wet snow surface,
- Or if you sink to your boot top in wet snow.
In general, if the snow surface freezes solid overnight, the snowpack will be stable in the morning and stability will decrease through the day as snow warms up. The snow surface hardness, rate of warming, duration of sunshine, aspect and elevation determine how fast stability will decrease through the day. Be aware that sunny aspects may have a wet snow avalanche danger while shadier slopes still have a dry snow avalanche danger. Getting off of steep slopes should be considered when, or before, the above signs of instability are present. Wet snow avalanches, whether loose snow or slabs, can be powerful, destructive and very dangerous. Conservative terrain choices, starting early in the day, and careful observations can keep you safe.
CORNICES
Cornices along ridgelines are massive and can break under the weight of a person (photo). Prolonged above freezing temperatures and rain make them weaker and possible to break naturally. They can break off suddenly and farther back than one might expect. Cornice falls can also entrain large amounts of loose snow or trigger slab avalanches. Stay far back from the edge of ridgelines and minimize exposure to slopes directly below cornices. Regardless of whether a cornice triggers a slide or not, a falling cornice is dangerous to anyone in its path.
DISCLAIMER
It does not matter if new snow falls or not, avalanches will continue to occur until the existing snowpack is mostly gone. Always assess the slope you plan to ride with diligence and safety in mind. Do not let your guard down. Travel with a partner, carry rescue gear and only expose one person at a time in avalanche terrain.
Have a safe and enjoyable spring and summer!
Mark, Alex, Ian and Dave
For more spring travel advice see this article from our GNFAC forecaster blog.