Advisory Archive

Last night the northern Gallatin Range picked up 7” of new snow with 1” falling around Big Sky, Carrot Basin and Cooke City. West Yellowstone and the Bridger Range were missed. West wind gusted into the 50s yesterday and lessened a bit overnight. Throughout the day, wind will blow from the west to northwest at 10-20 mph with gusts of 30-45 mph. Temperatures dropped abruptly into the teens last night and are only expected to climb into the mid-30s F today. Skies will clear this morning and no new snow is expected until Friday night.

Wet Avalanches

Today’s weather forecast of wind and relatively cool temperatures will keep the wet snow avalanche danger LOW. However, if the temperatures warm towards 40F and the wind lessens and the sun is out, the wet snow avalanche danger could rise to MODERATE. The good news is that it will be obvious: on sunny slopes the surface snow will quickly wet and you will see pinwheels rolling downhill that could trigger loose, wet avalanches.

There is no new snow to report this morning, only wind. A moist westerly flow will keep skies partly to mostly cloudy as west to southwest wind blows steady at 15-30 mph with frequent gusts of 40-50 mph. Temperatures are currently in the mid-20s F and will rise into the 40s today. Tonight temperatures will drop back into the 20s, wind will continue and snow will fall. By morning I expect 1-2” of new snow with Cooke City getting 3-4”. Tomorrow looks to be sunny followed by a wintry weekend of snow, cold temps and wind.

In the last 24 hours, the Northern Madison and the Northern Gallatin Ranges and mountains around Cooke City received 8-10” of new snow and the other ranges received 2-4”. Winds were 10-20 mph from the west and mountain temperatures are in teens to low 20s F. Today skies will become clear with west winds 10-20 mph and temperatures warming into the low 30s F.

WET SNOW AVALANCHES

Since Saturday night the mountains have received 8-14" of new snow. This new snow will rapidly destabilize as it warms up today and natural wet avalanches sliding on this weekend's melt-freeze crust are possible. When it becomes easy to form a snowball with the new snow and you start seeing small pinwheels rolling down slopes, move to shadier aspects because the change from stable to unstable can happen rapidly. Watch Ian's video from Mount Ellis to learn more. Today, the wet snow avalanche danger will increase to CONSIDERABLE and human triggered avalanches are likely. 

In the last 24 hours the mountains around Cooke City and West Yellowstone received an inch of snow yesterday morning, the Bridger Range picked up 2” last night and the rest of the advisory area remained dry. Winds were 5-15 mph from the southwest to the west. This morning, temperatures are in the teens to low 20s F. Temperatures today will rise into the upper 20s to low 30s F with winds from the west to southwest at 5-15 mph. By tomorrow morning the mountains around Big Sky and Cooke City will have 3-5” of new snow with other areas receiving 1-3”.

Last night temperatures dropped below freezing, wind died down and snow began falling. At 6 a.m. there is 7” of new snow in the Bridger Range, 2” in Cooke City and 4-5” everywhere else. Wind is from the west at 10-25 mph and mountain temperatures are in the 20s F. This morning another inch will fall and then skies will become partly sunny as mountain temperatures rise to near 40F.

There is no new snow this morning. Today starts out warm, dry, and mostly sunny. Winds are 10-30 mph out of the south and west with gusts of 30-50 mph. Temperatures are hovering around freezing. High temperatures today will be in the high 30s to 40s F. Winds will be 15-30 mph out of the SW. This afternoon a cold front will bring clouds and the chance of a brief drizzle before switching over to snow. Expect 1-3” of snow overnight.

WET AVALANCHES

With another very warm day in store, wet avalanches are the primary concern. Yesterday, numerous small wet slides were seen from the Bridgers to West Yellowstone (details). With only a light freeze overnight, surface crusts will break down quickly this morning on sunny slopes. Be alert as the snow surface becomes wet. If you’re sinking deeper than your ankles into wet snow, avoid steep slopes (video). Slides may break only in top few inches or gauge deeper, especially where the snowpack is thin and weak. Plan to be off steep, sunny slopes by the early afternoon, especially if the sun doesn’t become obscured by clouds. Across our entire advisory area, the wet snow avalanche danger will rise to MODERATE as surface crusts break down.

Sunny skies and warm temperatures continue today. There is no new snow this morning. Winds are 10-30 mph out of the south and west with gusts of 30-50 mph. Southwest winds with strong gusts will continue today. Temperatures this morning are in the high 20s to 30s F and will rise into 30s and 40s this afternoon. Tomorrow will start out warm with cooler air and precipitation moving in by tomorrow night.

WET AVALANCHES

The strong March sun and warm temperatures will increase the wet snow avalanche danger today. Yesterday, skiers in the Bridger Range triggered small wet sluffs on steep south facing slopes, but found that most slopes hadn’t warmed up quite enough for wet snow to become an issue (details). I found moist snow at the surface yesterday in the Lionhead area, but no significant wet snow avalanche hazard (video). Today’s slightly warmer temperatures will make wet snow a more widespread issue. Be on the lookout for pinwheels and rollerballs, loose wet point release avalanches, and sinking past your boot tops in slush as signs that the wet snow is becoming unstable. Once you see these signs, it’s time to get off steep slopes or move to the shade. Be particularly alert as you return to trailheads this afternoon on low elevation slopes that will be the warmest and are sheltered from cooling winds. Across our entire advisory area, the wet snow avalanche danger will rise to MODERATE on sun exposed slopes as the day heats up.

Yesterday the mountains around Cooke City picked up 2-3” of new snow while everywhere else got missed. Wind blew strong out of the west all day with gusts near 80 mph. Last night skies cleared and west winds lessened to 10-15 mph with gusts of 30 mph. Temperatures are in the teens this morning and will rise into the low 40s under mostly sunny skies and light west wind. Tomorrow will be even warmer.

WET AVALANCHES

Today’s sunny skies and warm temperatures will increase the wet snow avalanche danger.  Slopes getting direct sunshine will begin melting. Signs of instability in the moist surface snow are pinwheels rolling downhill, loose, wet point release avalanches, and sinking past your boot tops in wet snow. This is the first day of sunny skies, exceedingly warm temperatures, and mostly calm wind, a trio of factors that will wet the top foot of snow and increase wet avalanche activity. Ian made a video yesterday about today and tomorrow’s wet avalanche potential. For today, throughout our entire advisory area, the wet snow avalanche danger will rise to MODERATE on all sun exposed slopes.

There is no new snow to report, just wind and mild temperatures. Under partly to mostly cloudy skies mountain temperatures are in the 20sF and wind is blowing W-SW at 20-40 mph and gusts of 55 mph in Hyalite. Today will be partly cloudy and wind will continue to be strong from the southwest. Snow showers this afternoon will drop a trace to 1” of new snow. Tomorrow and Friday look to be warm and sunny giving us a taste of spring.

Last night the mountains received 1-3” of new snow. Winds averaged 15-30 mph from the west to southwest and gusted up to 65 mph at the Flanders weather station in Hyalite Canyon. This morning temperatures are in the teens to low 20s F. Today winds will blow 25-35 mph from the west in the northern ranges and 15-20 mph in the southern ranges. Temperatures will climb into the 20s to low 30s F. This morning Cooke City will receive a 1” of snow with a trace elsewhere before skies clear this afternoon.