February 18, 2023: The 2022-23 Season as of February 14
Be sure to click on "read more" below the graph for the complete article/post.
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It's time for a mid-season update on avalanche fatalities to date. In these updates we primarily focus on how the season compares to past seasons, going back ten years. At the end of the season a more comprehensive review can be prepared which looks at the reasons behind these incidents and what things, in general, could be done better or not overlooked. Our comprehensive review of last season is now available. Members can read a free online flipbook version or request a free Kindle version to be sent to their device. Non-members may purchase a print or Kindle version on Amazon.
This season has been a good one so far, with the number of fatal avalanche incidents well below the ten year average. There have been 5 such incidents, with the average being 10.78. All of these have been in continental/transitional snowpack climates with 3 in Colorado.
The Role of Snowpack
This season was supposed to be the third La Nina in a row, which some reports claimed would make it less typical than other such years. Which turned out to be true. The previous two seasons had very thin snowpacks all season long, with avalanches breaking on buried layers often at or near the ground. Most of this year's fatalities occurred early in the season when this was still true, with the most recent being January 9 just as the situation was changing.
The Role of Snowpack
This season was supposed to be the third La Nino in a row, which some reports claimed would make it less typical than other such years. Which has turned out to be true. The previous two seasons had very thin snowpacks all season long, with avalanches breaking on buried layers often at or near the ground. Most of this year's fatalities occurred early in the season when this was still true, with the most recent being January 9 just as the situation was changing.
From the end of December into early January a series of "atmospheric river" systems (a.k.a. "Pineapple Express" storms) brought very heavy storms, one after another, across the western US. While some might expect incidents during such heavy snowfall the danger was obvious, well publicized, and respected. Furthermore, in many areas accessing the backcountry (or even developed areas) was difficult to impossible due to the weather conditions.
While there were no fatalities during this series of storms there were exceptional avalanches. In Aspendell, California two or three homes were damaged or destroyed. Fortunately they were not occupied at the time. The slope which slid has no recorded history of reaching this far, although the possibility has been identified and is well known. (There is a second larger path which does have a history but did not cause any damage this time.) Exceptional weather such as this causes exceptional avalanches, regardless of snowpack structure or other details.
Following this extreme series of storms most of the US danger map posted by the Forest Service for the western US showed low danger, perhaps with a few locations edging into moderate. Any instabilities within this new snow would have settled out quickly and any previous weak layers became deeply buried.
Fatalities vs. Incidents
When the difference between the number of fatalities and the number of incidents is graphed it illustrates the problem in the past few seasons with multi-fatality incidents. Especially the 2020-21 season.
This graph will change in nature by the end of the season since, historically, multi-fatality incidents tend to be most common in spring mountaineering. There will be another spike for 2013 resulting from a single climbing accident on Liberty Ridge, Mt Rainier in which 6 climbers died. That was in June and thus does not appear on this partial-season chart.
Non-fatal Avalanche Incidents
We focus on fatal incidents for comparison purposes because they are known. There are clear records in the US (and in many other countries as well) of all accidents resulting in one or more fatalities. Non-fatal incidents may or may not be reported. Or recorded. In recent years more have come to the attention of the keepers of records, locally. But we have no way of knowing whether this is a result of more recreation, of more reporting, or whether there are more incidents on a per-capita (out of those recreating) basis.
This post will not review non-fatal avalanches but there have been plenty. Another trend in recent years is for more of these events to show up on YouTube which leads to more attention and sensationalization. Both by the people posting and by the mainstream media which is quick to pick up on this material. This can have effectively magnify perceptions concerning the number of these incidents. So we have no way of knowing how this season compares to others in this regard.
Summary
We can say that in terms of fatalities this season has not been a bad one so far. Only one out of six incidents resulted in more than one fatality (and it had just two). Since early January the snowpack, speaking in broad and general terms, has been much deeper and more stable than the past two seasons. It's been over one month since the last fatality.
We are still in the heart of winter and there will most likely be more reports in the next few months. Hopefully most regions are beyond any worry about ground-level weaknesses but future storms and the clear spells between them will present new risks, as well as the spring avalanche dangers when we get to that point.
The good news is that January and February are statistically the peak months for avalanche incidents. March generally marks a decline which accelerates in April and May.
Comments Disabled - Now that some time has passed and a few hundred spam comments have been deleted the comments are closed. If you would like to add anything, or make a guest post, contact us at snow@csac.org and we will make it happen.
It's time for a mid-season update on avalanche fatalities to date. In these updates we primarily focus on how the season compares to past seasons, going back ten years. At the end of the season a more comprehensive review can be prepared which looks at the reasons behind these incidents and what things, in general, could be done better or not overlooked. Our comprehensive review of last season is now available. Members can read a free online flipbook version or request a free Kindle version to be sent to their device. Non-members may purchase a print or Kindle version on Amazon.
This season has been a good one so far, with the number of fatal avalanche incidents well below the ten year average. There have been 5 such incidents, with the average being 10.78. All of these have been in continental/transitional snowpack climates with 3 in Colorado.
The Role of Snowpack
This season was supposed to be the third La Nina in a row, which some reports claimed would make it less typical than other such years. Which turned out to be true. The previous two seasons had very thin snowpacks all season long, with avalanches breaking on buried layers often at or near the ground. Most of this year's fatalities occurred early in the season when this was still true, with the most recent being January 9 just as the situation was changing.
The Role of Snowpack
This season was supposed to be the third La Nino in a row, which some reports claimed would make it less typical than other such years. Which has turned out to be true. The previous two seasons had very thin snowpacks all season long, with avalanches breaking on buried layers often at or near the ground. Most of this year's fatalities occurred early in the season when this was still true, with the most recent being January 9 just as the situation was changing.
From the end of December into early January a series of "atmospheric river" systems (a.k.a. "Pineapple Express" storms) brought very heavy storms, one after another, across the western US. While some might expect incidents during such heavy snowfall the danger was obvious, well publicized, and respected. Furthermore, in many areas accessing the backcountry (or even developed areas) was difficult to impossible due to the weather conditions.
While there were no fatalities during this series of storms there were exceptional avalanches. In Aspendell, California two or three homes were damaged or destroyed. Fortunately they were not occupied at the time. The slope which slid has no recorded history of reaching this far, although the possibility has been identified and is well known. (There is a second larger path which does have a history but did not cause any damage this time.) Exceptional weather such as this causes exceptional avalanches, regardless of snowpack structure or other details.
Following this extreme series of storms most of the US danger map posted by the Forest Service for the western US showed low danger, perhaps with a few locations edging into moderate. Any instabilities within this new snow would have settled out quickly and any previous weak layers became deeply buried.
Fatalities vs. Incidents
When the difference between the number of fatalities and the number of incidents is graphed it illustrates the problem in the past few seasons with multi-fatality incidents. Especially the 2020-21 season.
This graph will change in nature by the end of the season since, historically, multi-fatality incidents tend to be most common in spring mountaineering. There will be another spike for 2013 resulting from a single climbing accident on Liberty Ridge, Mt Rainier in which 6 climbers died. That was in June and thus does not appear on this partial-season chart.
Non-fatal Avalanche Incidents
We focus on fatal incidents for comparison purposes because they are known. There are clear records in the US (and in many other countries as well) of all accidents resulting in one or more fatalities. Non-fatal incidents may or may not be reported. Or recorded. In recent years more have come to the attention of the keepers of records, locally. But we have no way of knowing whether this is a result of more recreation, of more reporting, or whether there are more incidents on a per-capita (out of those recreating) basis.
This post will not review non-fatal avalanches but there have been plenty. Another trend in recent years is for more of these events to show up on YouTube which leads to more attention and sensationalization. Both by the people posting and by the mainstream media which is quick to pick up on this material. This can have effectively magnify perceptions concerning the number of these incidents. So we have no way of knowing how this season compares to others in this regard.
Summary
We can say that in terms of fatalities this season has not been a bad one so far. Only one out of six incidents resulted in more than one fatality (and it had just two). Since early January the snowpack, speaking in broad and general terms, has been much deeper and more stable than the past two seasons. It's been over one month since the last fatality.
We are still in the heart of winter and there will most likely be more reports in the next few months. Hopefully most regions are beyond any worry about ground-level weaknesses but future storms and the clear spells between them will present new risks, as well as the spring avalanche dangers when we get to that point.
The good news is that January and February are statistically the peak months for avalanche incidents. March generally marks a decline which accelerates in April and May.
