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Snowpack Summary April 5, 2024
Posted by Allen Giernet @ 7:30 pm (this summary expires in 24 hours)
This summary applies to backcountry areas only.
The Bottom Line –
Wind slab avalanches will be found on Southeast, East and Northeast aspects at the higher elevations below ridge lines or along leeward sides of gullies. You may find windslabs on other aspects due to topographical influence and variable winds. Though generally not large these avalanches can knock you off your feet in committing terrain and entrain recent storm snow to become larger. Moderate to strong Southwest through West to Northwest winds will have transported snow and will be moving new snow tomorrow. Look for wind scoured areas, textured snow surfaces, blowing snow and pillowed or hollow sounding firm snow to indicate wind slab development. Loose dry avalanches will be possible with the forecast snow amounts last night and through today on all but wind scoured aspects (SE, E & NE) at mid and high elevations. To avoid these problems stick to wind sheltered areas and slopes <30° if significant snow has accumulated. Following past few days of warm temperatures and sun expect to find firm crusts and firm fast conditions at lower elevations and possibly higher on the mountain on southern aspects and solar exposed terrain.
We are still operating on very limited on the ground data. If you are venturing out share any information you gather on our Submit Report page. The page is operating again and all reports are being retrieved and slowly posted. Most recent reports are up on the website.
Posted by Allen Giernet @ 7:30 pm (this summary expires in 24 hours)
This summary applies to backcountry areas only.
The Bottom Line –
Wind slab avalanches will be found on Southeast, East and Northeast aspects at the higher elevations below ridge lines or along leeward sides of gullies. You may find windslabs on other aspects due to topographical influence and variable winds. Though generally not large these avalanches can knock you off your feet in committing terrain and entrain recent storm snow to become larger. Moderate to strong Southwest through West to Northwest winds will have transported snow and will be moving new snow tomorrow. Look for wind scoured areas, textured snow surfaces, blowing snow and pillowed or hollow sounding firm snow to indicate wind slab development. Loose dry avalanches will be possible with the forecast snow amounts last night and through today on all but wind scoured aspects (SE, E & NE) at mid and high elevations. To avoid these problems stick to wind sheltered areas and slopes <30° if significant snow has accumulated. Following past few days of warm temperatures and sun expect to find firm crusts and firm fast conditions at lower elevations and possibly higher on the mountain on southern aspects and solar exposed terrain.
We are still operating on very limited on the ground data. If you are venturing out share any information you gather on our Submit Report page. The page is operating again and all reports are being retrieved and slowly posted. Most recent reports are up on the website.
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Dry Loose avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.
General discussion
Another Shot of winter brings us the concerns of wind slab avalanches and dry loose avalanches. Following a brief spring window with sunny skies and warm temperatures, crust will have developed at the lower elevations and the higher elevations on solar exposed and southerly aspects. The recent cold storm with moderate to strong SW to NW winds and light snow will continue developing wind slabs and potentially poor bonding to the old snow surface. Expect to find wind slabs on the easterly aspects SE, E & NE due to variable winds and possibly on other aspects due to topographic influence. Assess conditions in the Baldy Bowl prudently. Wind transport will continue overnight into tomorrow. Light snow will also create the potential for dry loose avalanches on all aspects at mid elevations and on W through SE and wind sheltered areas at ridge top elevations. Lower elevations may present with dust on crust conditions and possible slide for life scenarios depending on much snow accumulated and how firm crusts have become with the very cold temperatures. Expect to find variable conditions throughout the terrain as you travel and assess the snowpack carefully. Use good judgement if uncertain and increase your safety margins. With warming in the afternoon and sunny skies forecast the possibility for small loose wet avalanches may develop especially on southerly aspects and at lower elevations. Our uncertainties are how much snow has actually fallen at different elevations and how firm the lower elevation melt freeze crusts will be.
Please share any information when you are out in the mountains. Even a photo is helpful. Submit observations to the Submit Report page.
Another Shot of winter brings us the concerns of wind slab avalanches and dry loose avalanches. Following a brief spring window with sunny skies and warm temperatures, crust will have developed at the lower elevations and the higher elevations on solar exposed and southerly aspects. The recent cold storm with moderate to strong SW to NW winds and light snow will continue developing wind slabs and potentially poor bonding to the old snow surface. Expect to find wind slabs on the easterly aspects SE, E & NE due to variable winds and possibly on other aspects due to topographic influence. Assess conditions in the Baldy Bowl prudently. Wind transport will continue overnight into tomorrow. Light snow will also create the potential for dry loose avalanches on all aspects at mid elevations and on W through SE and wind sheltered areas at ridge top elevations. Lower elevations may present with dust on crust conditions and possible slide for life scenarios depending on much snow accumulated and how firm crusts have become with the very cold temperatures. Expect to find variable conditions throughout the terrain as you travel and assess the snowpack carefully. Use good judgement if uncertain and increase your safety margins. With warming in the afternoon and sunny skies forecast the possibility for small loose wet avalanches may develop especially on southerly aspects and at lower elevations. Our uncertainties are how much snow has actually fallen at different elevations and how firm the lower elevation melt freeze crusts will be.
Please share any information when you are out in the mountains. Even a photo is helpful. Submit observations to the Submit Report page.
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To better understand the challenges and potential variability over the large area we are producing information for please read our Snowpack Summary - Format and Limitations
Disclaimer:
This Bulletin is designed to generally describe conditions where local variations always occur. Travelers are advised to exercise caution and make slope specific evaluations. As always, please treat this bulletin with appropriately guarded skepticism and make your own assessments. Help to provide more information to the community by reporting your observations
This Bulletin is designed to generally describe conditions where local variations always occur. Travelers are advised to exercise caution and make slope specific evaluations. As always, please treat this bulletin with appropriately guarded skepticism and make your own assessments. Help to provide more information to the community by reporting your observations
Latest Observtions
Click on the observation to go to the full report
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Avalanche Observation 04-1-24 Angeles Crest
Comment April 1st 2024 9.4k above Angeles crest New snow approx 50 cm at 6800 ft 5-7cm rain/moisture/radiation crust on all aspects below 7800. Above 7.8k the crust became unnoticeable to nonexistent as the snow and higher elevation environment transitioned. Little to no rapid warming above 8k as rime and snow on the trees remained quite and still with no melting, which clued into below freezing temperatures. We observed large new cornices with some natural cornice failure on a north facing ridge above 9k. We also observed some wind loaded features that failed under foot as we descended. Several wind loaded features approx three meters in length by one meter in width failed beneath me and another as we traversed an exposed feature. It was not enough to catch and carry but did raise some concern on exposed convexities. No other instability in the higher terrain snowpack was observed. Below 8k was another story. As we descended below 8k at approx 16:00hrs, nearly all exposed west and east aspects showed obvious and expansive signs of wetloose debris and slides. Some slides and slide paths were respectively D2/R3 |
Pro. Snow/ Avalanche Observation 04-1-24 Angeles Crest / Waterman
Comment - 10:09am Sky - Ovc Wind - L - NE Temp - NO Several small loose wet avalanches on N to NW aspects approximately 7,000' + near avalanche canyon and Winston springs and along road cuts. Appeared to be triggered by Snow shedding from trees or near rocks. 10:40 Sky-Ovc Wind - M-ENE Precip.-0 Temp - .5C Snow transport active. Seems like possible light rain or fog affected snow. Breakable crust & snow still on trees but affected by moisture 1:10p kicked wind lip broke loose and immediately self arrested 1:54 6970’ Temp - 6C As clouds broke in the afternoon snow surface softened and became poor riding conditions. Upon leaving I noted numerous loose wet avalanches up to near the ridgelines on Northerly aspects in Both Avalanche Canyon and Winston Springs. Day began with crust on surface and I suspect low clouds noted on the drive in may have contributed moisture to snow surface. Potential greenhouse effect from clouds and above freezing temperatures the day before. Higher elevations may not see this condition. As the softening surface refreezes overnight crust will be more solid and could contribute to fast firm conditions in the morning. |
Avalanche Obs 04-1-24 Alta Diablo
Comment - Small wet slides carrying down the top of Alta’s steeps ~40deg to the less steep parts. We triggered a number of them. Did not carry us, not warm enough to be super large. |
Snowpack Obs 03-30-24 Big Bear area
Comment - Kick test propagation about 10-15 feet and width of splitboard at 35* North aspect, storm snow accumulated about a foot in 18 hours+/-. Break happened in between new snow layers, not at the older ice layer. |
General Caution
You should always use safe terrain management and carry avalanche rescue equipment in the backcountry. Most avalanches are triggered by someone in the party or the victim. Practice with your rescue gear often and be prepared should the worst happen. Though we do not have an avalanche forecast center in this area as of yet, the information posted and shared here as well as the resources available on this site will help to make informed decisions for your backcountry travels. Use avalanche forecasts in your travels wherever available and be aware that avalanche ratings are general information. Elevation, location, geographic variability’s, slope aspect and angle all have effects on the particular area you travel in. This is only one piece of the information you should use in your decision making process. There is no substitute for avalanche education, for more resources and information as well as education please refer to our resources page.
You should always use safe terrain management and carry avalanche rescue equipment in the backcountry. Most avalanches are triggered by someone in the party or the victim. Practice with your rescue gear often and be prepared should the worst happen. Though we do not have an avalanche forecast center in this area as of yet, the information posted and shared here as well as the resources available on this site will help to make informed decisions for your backcountry travels. Use avalanche forecasts in your travels wherever available and be aware that avalanche ratings are general information. Elevation, location, geographic variability’s, slope aspect and angle all have effects on the particular area you travel in. This is only one piece of the information you should use in your decision making process. There is no substitute for avalanche education, for more resources and information as well as education please refer to our resources page.
