|
Your Support Helps
|
|
An Avalanche Watch is in Effect
Travel In Avalanche Terrain is No Advised
Travel In Avalanche Terrain is No Advised
Snowpack Summary March 15, 2023
Posted by Allen Giernet @ 7:30 am (this summary expires in 24 hours)
This summary applies to backcountry areas only.
The Bottom Line –
The snowpack has been loaded with a significant amount of water except the highest elevations. Human triggered Loose Wet avalanches will be likely in moisture laden snow. Steer clear of slopes over 30° while the storm moves through today and allow the snowpack time to absorb the added water weight and refreeze over the next few days. High elevation snow above 9,000’ is forecast with strong Northwest to West winds could form small Wind Slabs above rain line below ridgelines and along gullies. Look for the signs of windrifted snow at the highest elevations.
Please share your observations with us at the avalanche center Submit Reports page.
Posted by Allen Giernet @ 7:30 am (this summary expires in 24 hours)
This summary applies to backcountry areas only.
The Bottom Line –
The snowpack has been loaded with a significant amount of water except the highest elevations. Human triggered Loose Wet avalanches will be likely in moisture laden snow. Steer clear of slopes over 30° while the storm moves through today and allow the snowpack time to absorb the added water weight and refreeze over the next few days. High elevation snow above 9,000’ is forecast with strong Northwest to West winds could form small Wind Slabs above rain line below ridgelines and along gullies. Look for the signs of windrifted snow at the highest elevations.
Please share your observations with us at the avalanche center Submit Reports page.
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
General Summary
#1 Loose Wet avalanche – Human triggering will be likely on all aspects due to over 2” of water added to the snowpack up to 9,000’. There is up to another inch of water forecast for today up to 8,800’ to add to the load on the snowpack. Water saturated snow will be easily triggered and potentially entrain significant amounts of snow as it travels downhill. The snowpack will take some time and overnight freezing to adjust to the added loading. Other hazards will be present such as flooding and rockfall/ mudslides as you travel into the mountain. Though some roads have been open, access into the mountains is still limited and may become more limited as this storm moves through. Be aware of road closures and restrictions to allow residents and safety personnel access to their homes and communities.
Outlook – As this storm moves out colder overnight temperatures are forecast for the next couple of days and fast firm conditions will become the number one hazard. Be prepared with proper equipment and anticipate variable conditions. Into the weekend and next week some smaller storms are forecast watch the weather forecast as the approach and adjust plans accordingly.
Exercise caution if venturing out into the mountains and use avalanche protocols, travel with a partner and bring your beacon, shovel and probe.
Please share any information when you are out in the mountains. Even a photo is helpful. Submit observations to Submit Reports page.
#1 Loose Wet avalanche – Human triggering will be likely on all aspects due to over 2” of water added to the snowpack up to 9,000’. There is up to another inch of water forecast for today up to 8,800’ to add to the load on the snowpack. Water saturated snow will be easily triggered and potentially entrain significant amounts of snow as it travels downhill. The snowpack will take some time and overnight freezing to adjust to the added loading. Other hazards will be present such as flooding and rockfall/ mudslides as you travel into the mountain. Though some roads have been open, access into the mountains is still limited and may become more limited as this storm moves through. Be aware of road closures and restrictions to allow residents and safety personnel access to their homes and communities.
Outlook – As this storm moves out colder overnight temperatures are forecast for the next couple of days and fast firm conditions will become the number one hazard. Be prepared with proper equipment and anticipate variable conditions. Into the weekend and next week some smaller storms are forecast watch the weather forecast as the approach and adjust plans accordingly.
Exercise caution if venturing out into the mountains and use avalanche protocols, travel with a partner and bring your beacon, shovel and probe.
Please share any information when you are out in the mountains. Even a photo is helpful. Submit observations to Submit Reports page.
|
General Mountain Weather Forecast |
Weather Page Link
Click on the links below for the latest information
Click here for this Season's Snow Pack Summaries
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
|
Observation type -
Snowpack Location - Mt. San Antonio Date (yyyymmdd) - 20230309 Comment - We left Manker Flat area at 5:15am and reached the top of Mt. San Antonio (Baldy) at about 10:30am. We ascended mostly via crampons as the snow was still a bit too iced for skinning. No recent avalanches were observed on the S face of "Baldy Bowl" during our ascent on S face. No cracking, woomfing, or hollowness was observed during our ascent on S face. At the top of Mt. San Antonio, we observed moderate to strong winds. Although no snow was being actively transported during our observation, we witnessed heavily wind affected snow at the top of the ridge and peak. Some wind loading was observed on some aspects at the peak elevation, but our main concern was ice. Blue ice was observed on the ridge around the peak. Some avalanche activity was observed on distant extreme terrain on NE aspects off Telegraph and Ontario Peak. We descended down the NW face of Mt. San Antonio. We avoided the wind loaded leeward slopes, opting instead for barely edgeable ice crust for the first 100 feet or so. This ice eventually yielded to soft wind effected snow. We eventually came to the crux 3/4 of the way down and opted to down climb with crampons and axes. We did observe one small area R1? of snapped trees (but no other debries, indicating an older avalanche) on an E facing aspect below treeline. After completing descent, we climbed up the R ridge, gaining the col between San Antonio and Harwood and skied down the S face of San Antonio. No wet slide activity was observed on our descent down the S face. These observations occurred before a rain/snow event on March 10th and 11th. |
Observation type
Snowpack Location - Mt. Baden Powell Date (yyyymmdd) - 20230305 Comment - Road Mount Baden Powell right after the big storm and got one really good day of powder. Then came back two days later and the sun had already baked it and re-froze a bad firm crust on the top :( Firm snow and crust exists all the way up to 8000 feet or more. Noticed a slightly weak layer about 12 inches deep in the snow pack and did some testing and concluded it is not a major concern, though it did slide with extremely isolated and with extreme pressure on the snow pack. |
Observation type
Snowpack Location - Wrightwood Date (yyyymmdd) -20230301 Comment The epic snow event of 2023 has delivered as promised, and more. Below are some contemporaneous notes from observations at/near approximately 6,400ft in the Swarthout Valley. - Very cold, dry snow fell on 2/23 night along with gusty winds. Pockets of slabby windboard were observed on leeward slopes. - Friday 2/24 morning through Saturday 2/25 afternoon was the main event, with consistent snowfall rates of 6-9cm/hr. Best guess is snowfall ratios were 12-15:1. Totals were approx. 1.5 meters. Likely 2-3m in the high country. - Sunday 2/26 was clear and mild, with slightly above-freezing temps up to ~7000ft. Solar aspects were turning to hot pow and mank. Some - Snow and gusty winds resumed evening of 2/28, increasing in intensity overnight. By Wednesday 3/1 there was 20-30cm of new snow, with local pockets of 40-50cm in wind-loaded areas. - Several D1.5 natural avalanches were spotted on ~40deg slopes around 7300ft on 2/26. - I observed several large “whumphs” while shoveling snow from my car onto the adjacent slope, presumably from the added load. - Tl;dr – a LOT of snow has fallen in the past week, on top of variable surfaces ranging from bare earth to refrozen corn to old facets. We are now faced with a much deeper and more complex snowpack than is typical for the SoCal mountains. Roads are virtually impassable in mountain towns, so please respect residents by obeying CalTrans and CHP closures. |
Observation type
Snowpack Location - Wrightwood Date (yyyymmdd) - 20230225 Comment - Ventured out with a conservative route plan as this mega storm was winding down to see how much fell and what the snowpack is like. My partners and I toured to a ~25deg stand of oak and pine that would almost certainly never be skiable in normal years. Snow in our low-ish elevation tour seems right side up with high quality cold, dry powder rounding out the storm. Pit at ~6500ft on a 25deg North slope. 110cm deep 0-5 knife hard ice (remnants from earlier this winter) 5-55 4F 55-110 fist CT14 at 40cm, Q3 shear Snow hasn't bonded well to the icy/corn base but wasn't reactive in column test We did observe a D1 dry loose slide on a small ~40deg slope on our return home. However, there were not other observed signs of instability during our tour. |
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.
