Avalanche Forecast
Jan 10th, 2019–Jan 11th, 2019
Alpine
3:
Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2:
Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2:
Moderate
The avalanche danger rating below treeline will be moderate
Alpine
2:
Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2:
Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2:
Moderate
The avalanche danger rating below treeline will be moderate
Regions: Snoqualmie Pass.
The bottom line: The weather and the snowpack will be transitioning Friday. Be patient as the snowpack adjust after this recent period of active weather. Strong winds formed wind slabs in a variety of locations. You will need to look for fresh cornices and snow drifts to identify and avoid wind loaded slopes greater than 35 degrees. If the sun comes out, don’t get surprised by loose wet avalanches coming from steep southerly slopes.
Regional Synopsis
January 10, 2019
We’re about a month into our avalanche forecasting season, and what a wild month it has been. We’ve seen the snowpack grow from near non-existent to over a 100 inches deep at Mt Baker. We’ve seen avalanche warnings blanket our coverage area, had several widespread large natural avalanche cycles, and seen persistent weak layers plague nearly every zone. While the active weather pattern has been a welcomed sight, it’s hard to catch your breath.
It looks like this weekend, and extending into next week, we are entering a calm period in the weather. High pressure over Idaho and Montana will keep Pacific storms at bay for at least the short term. As we enter this period of nice weather, there are a few things on our mind here at the avalanche center.
Old Persistent Weak Layers
A high elevation rain event on January 3rd did us a favor in many locations. Besides heavily stressing old weaklayers, the rain created a very strong met-freeze crust, making it extremely difficult to trigger deep avalanches.
There are a few exceptions, and they can be found mainly in the eastern forecast zones. The East-North zone around the Methow Valley and WA Pass did not experience significant rain above 5500 ft, potentially leaving some older weak layers in tact. Areas further east including, but not limited to, Icicle Creek and the Wenatchee Mountains did not receive enough rain to form a strong thick crust. In all of these area, older persistent weak layers are still suspect.
Higher Elevations and Remote Trailheads
Stormy weather over the last month has been keeping most of us closer to common trailheads and recreating at near and below treeline. With nice weather on tap, some of you may be thinking about heading into higher elevation terrain and exploring around more remote trailheads. If you are heading out, take time to consider a few key pieces of information.
If you’re heading into higher elevation terrain, remember we don’t have much information about these snowpacks, and therefore have a higher degree of uncertainty. Photo: SimonTrautman
We’d like to thank our NWAC Community for all the wonderful public observation this year. If you are heading out into the mountains, we appreciate you taking the time to let us know what you saw. This is a great way to contribute to the creation of your avalanche forecast. You can submit observations here.
Enjoy the sunshine!
We’re about a month into our avalanche forecasting season, and what a wild month it has been. We’ve seen the snowpack grow from near non-existent to over a 100 inches deep at Mt Baker. We’ve seen avalanche warnings blanket our coverage area, had several widespread large natural avalanche cycles, and seen persistent weak layers plague nearly every zone. While the active weather pattern has been a welcomed sight, it’s hard to catch your breath.
It looks like this weekend, and extending into next week, we are entering a calm period in the weather. High pressure over Idaho and Montana will keep Pacific storms at bay for at least the short term. As we enter this period of nice weather, there are a few things on our mind here at the avalanche center.
Old Persistent Weak Layers
A high elevation rain event on January 3rd did us a favor in many locations. Besides heavily stressing old weaklayers, the rain created a very strong met-freeze crust, making it extremely difficult to trigger deep avalanches.
There are a few exceptions, and they can be found mainly in the eastern forecast zones. The East-North zone around the Methow Valley and WA Pass did not experience significant rain above 5500 ft, potentially leaving some older weak layers in tact. Areas further east including, but not limited to, Icicle Creek and the Wenatchee Mountains did not receive enough rain to form a strong thick crust. In all of these area, older persistent weak layers are still suspect.
Higher Elevations and Remote Trailheads
Stormy weather over the last month has been keeping most of us closer to common trailheads and recreating at near and below treeline. With nice weather on tap, some of you may be thinking about heading into higher elevation terrain and exploring around more remote trailheads. If you are heading out, take time to consider a few key pieces of information.
- At higher elevations the snowpack is very deep and wintery. This stands in stark contrast to the lack of snow at lower elevations. The snowpack you’ve seen on previous outings this winter, doesn’t represent what you will encounter at higher elevations.
- We have not received much information about the above treeline nor remote location snowpacks. That means we have a high degree of uncertainty in these areas.
- You will need to make observations as you travel to confirm if the avalanche forecast is applicable the the area where you are traveling. When observations lineup with the information in a forecast, its valid. If you see observations that don’t lineup, it’s time to take a step-back.
- If you are heading into our regions highest alpine terrain, remember, NWAC forecast apply to areas below the main Cascade crest, or about 8000 ft. So, if you plan to travel to higher elevations on Mt Baker, Mt Shuksan, Mt Rainier, Mt Hood, or similar areas, you will need the skills and information to evaluate the terrain and snowpack.
If you’re heading into higher elevation terrain, remember we don’t have much information about these snowpacks, and therefore have a higher degree of uncertainty. Photo: SimonTrautman
We’d like to thank our NWAC Community for all the wonderful public observation this year. If you are heading out into the mountains, we appreciate you taking the time to let us know what you saw. This is a great way to contribute to the creation of your avalanche forecast. You can submit observations here.
Enjoy the sunshine!
Weather Forecast
Weather Synopsis for Friday night through Sunday
A high-amplitude ridge is centered over Idaho on Friday afternoon. The high pressure will cut off late Friday and will expand slightly westward, increasing the already very warm temperates at mid and upper-levels Saturday night and Sunday over our region. The ridge and subsequent high will block weather systems from moving eastward, but mid and high-level clouds will remain with us at times into Saturday as a week low skirts northward offshore, brushing the Olympics with some lowering clouds and a possible sprinkle.
Moderate easterly flow will be sustained throughout the forecast period with cooler air at low levels to the east of the Cascade Crest warming as it descends to the Puget Sound lowlands.
A low-level inversion has developed as evidenced by the two stations at Washington Pass where the upper station is above freezing on Friday afternoon. In general, colder air sinks into the deeper valleys, and without wind to stir it up, low clouds and fog will predominate day and night. The easterly flow will suck the low clouds and fog through the lower mountain gaps such as Snoqualmie Pass keeping the passes cool.
More sunshine is expected by Saturday afternoon with mostly clear skies through Sunday as the inversion and moderate east flow continue.
Avalanche Problems
Wind Slabs
“Unusual places” is the phrase we’ve heard several times this about recent wind slabs. Indeed observations in the field found wind slabs on a variety of aspect, on cross-loaded features, on slopes well below ridge-line, and in areas often wind scoured. You need to look and feel for wind slabs if you travel above the recent rain line. Fresh cornices, the snow blown out of the trees, and firmer, hollow-like snow under you are all signs wind slabs may be nearby. Use observations like these to identify and avoid windloaded slopes greater than 35 degrees. In some areas wind slabs may be hiding under a few inches of softer, recent snow.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 2 - 2
Loose Wet
If the sun come out, expect loose wet avalanche from steep, sunny slopes. Don’t let this easier to predict avalanche problem catch you off guard. Don’t linger in confining locations like gullies and near creeks, where even small loose avalanche can bury you deeply. At higher elevations, a loose avalanche may act as a trigger for a deeper, wind slab avalanche. If you see natural loose wet avalanche activity, limit the time you spend traveling below larger wind loaded slopes.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 1