Avalanche Forecast
Jan 11th, 2019–Jan 12th, 2019
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
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 snowpack is gaining strength and we are seeing a decrease in avalanche danger around Snoqualmie Pass. That doesn’t mean you can’t trigger an avalanche Saturday. You may still encounter lingering wind slabs on convex rollovers in higher elevation terrain. As the sun comes out and temperatures warm, watch for rollerballs and fan-shaped avalanches that indicate you may experience a loose wet avalanche.
Snow and Avalanche Discussion
Rain impacted the snow up to about 4500 feet in the Snoqualmie Pass area this week. This has resulted in difficult travel conditions below treeline. Expect breakable crust, thick heavy snow, and numerous open creeks as you travel.
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 Saturday night through Monday
A ridge of high pressure anchored over the Intermountain West will lead to a dry weekend. A weak and splitting frontal system offshore has spread some high clouds over the area today.
There is some nuance to the freezing level forecast with offshore easterly flow continuing to draw colder air and low clouds through the Cascade Passes while much milder air can be found at higher elevations and along the west slopes of the Cascades and Olympics.
The cold pool along the east slopes of the Cascades will slowly erode and moderate through Monday with freezing levels on the rise, but low clouds and cooler temperatures will persist along the lower slopes.
Light to moderate easterly flow through the Cascade Passes and at ridge-crest for places like Crystal Mountain will also persist into Monday despite the overall warming trend.
Avalanche Problems
Wind Slabs
Observations this past week frequently included “wind slabs in unusual locations.” These slabs are now a few days old and beginning to heal. If you head into higher elevation areas, keep this problem on your mind. You may still encounter a lingering wind slab on a variety of very steep, convex, or unsupported slopes. If you encounter firm, hollow snow surfaces, or see smooth pillow-like wind deposits, expect wind slabs on nearby slopes.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 3 - 3
Loose Wet
Friday remained cloudy in most locations, so the loose wet avalanche problem did not materialize. We’re expecting sunshine and warmer temperatures on Saturday, which will give us another chance of loose wet avalanches. Don’t underestimate this easier to predict avalanche problem. If the sun comes out, expect loose avalanches from steep, rocky, sunny slopes. Even small avalanche can be dangerous in high consequence terrain, such as above cliffs or in gullies. If you see rollerballs or fan-shaped avalanches, it’s time to avoid traveling on similar slopes greater than 35 degrees.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1