How Much Snow?
15th March 2021
The Scottish Avalanche Information Service issues information to support permitted activity under current Scottish Government guidance.
This blog is intended to provide hazard and mountain condition information to help plan safer mountain trips.
After quite a few poor visibility days, it finally (briefly) cleared today and there were views into Coire an Lochan. There were some quite large and unstable looking cornices around, and evidence of overnight avalanche activity in Easy Gully.
Interestingly the amount of snow in Coire an Lochain seemed different compared to other years. The amount of snow seemed average for the middle of March.
See graphs below for information on this.
Fresh Drifts behind snow fences. There has been a reasonable amount of snow over he past few days.
The top of Easy Gully. Notice the crown wall running diagonally on the far side of the gully. This avalanche was likely triggered last night from cornice collapse.
Lots of fresh and not very stable looking cornices about.
The view into Coire an Lochan today 15th March 2021
For comparison the same view into Coire an Lochan on the 20th of March 2020 on my final day forecast that before the covid lockdown occurred. A fair bit more snow a year ago than there was today.
By summing the snow index recorded when doing the snow pit it is possible to see the amount of snow that has fallen each season up to the 15th of March. There are a few issues with this method, for example the different start dates each season. This season started around 10 days earlier than some previous seasons due to the early snow. Also a slight change in the way that we recorded the data means years before about 2013 might be under-reading a slightly. The data also is just the total accumulation, and does not count melting, which of course happens regularly through the winter months. Despite these issues, I feel the general findings are quite robust. These are that this year is somewhere in the middle of the pack (6 snowier years, 7 less snowy), more snow than the likes of 2017 and 2019 but not as much snow as the likes of last winter (which would agree with the picture comparison above).
The comparison of this winter and last winter in cumulative snow fall. Last winter forecasting started around the 12th of December, and that is why there is nothing recorded before that date, this year we started on the 2nd of December. Of course in almost all years there has been at least some snow falls before we start forecasting. This year there was more snow through until mid February, which agrees with that I remember about last season as compared to this season. However, heavy snow in late February and early March last season meant that by the 15th of March there was more snow last year than there was today.
Comments on this post