2023 High Snowpack Conditions: Jinxing snow discussion

[kpeter]

Just in the last few days the accumulated totals have put the state-wide graph on par with 1983 more than 2017, and we have a couple more weeks of storms expected. In the south, especially, we are probably going to exceed 1983, and if it keeps coming we could exceed 1983 everywhere.

While I am pleased about breaking the drought, I am increasingly worried about serious flooding. And I know my Sierra backpacking season--which relies on early season backpacking--will be severely curtailed.

I've noticed that snowpack in Idaho is just a little above normal. Perhaps this is the year I return to my roots and abandon the Sierra for a season.

[texan]

A point of clarification on how ski resorts report snowfall and snow depths. They will state a season total, which is how much snow they have recieved, measured each day as it falls. That 633 inches for Dodge is that number. That is NOT the snow depth on the ground, nor is it intended to mean that. The snow depth on the ground is reported as "base depth" or just base. At Dodge that is currently 111 to 144 inches, depending on where you are on the mountain.

Good Point Paul, I should have said annual total or season total your right. Leavitt Lake has over twenty feet snow right now. The snow sensor was at 248 inches this morning which is huge. I wonder what the annual snow fall total is there. I bet its a lot.

Texan

[paul]

The Leavitt Lake sensor is always fun because it gets such big numbers. Right now I think only one sensor shows a higher water equivalent - Farewell Gap. Unfortunetly the depth sensor is not working at Farewell Gap. Oddly, there are no manual surveys at Leavitt Lake so we never get a cpmparison between the manual numbers and the sensor like you get from some other locations. Usually there is some difference between the two, if only because the sensor is at one spot, while the manual survey measures the depth and water content at several locations along a line between two marked points and the averages of those numbers are the numbers published for that station.

[paul]

It is pretty interesting and educational to play around with the interactive graph on the CDEC snow website, comparing different years at different points in the year. For instance, comparing 2010-11 with 2016-17. At the beginning of March, 2011 is well behind 2017 for both central and south, but by the end of march, they are very close, especially in the south, where they stay neck and neck until mid-may when 2011 takes the lead and stays higher until the end of June. Looking at their snowpack report in ma for, it looks like the South region covers the bulk of the area from Yosemite southwards, so that’s where I focus my attention generally. Plugging in 2018-19, we see it close to very close to 2011 and 2017 at the end of march, then it drops off faster for a while but them gets a bump in mid-may and comes back up to be right in the same range by the end of May.
The takeaway, for me, is that there is a lot of variation in how much snow falls in April and May, and in how much melts in those months. The line for this year is above everything else, but where it goes from here is pretty hard to predict. Right now the forecasts are for more snow – I looked at a point forecast for Blackcap Basin and it shows snow almost every day for the next week. This Tuesday: “Snow. The snow could be heavy at times. High near 27. Windy, with a southwest wind 20 to 30 mph increasing to 30 to 40 mph in the afternoon. Winds could gust as high as 55 mph. Chance of precipitation is 90%. New snow accumulation of 35 to 41 inches possible.”
Then Tuesday night: “Snow before 11pm, then snow showers likely after 11pm. The snow could be heavy at times. Some thunder is also possible. Low around 15. Very windy, with a southwest wind 40 to 45 mph decreasing to 30 to 35 mph in the evening. Winds could gust as high as 65 mph. Chance of precipitation is 100%. New snow accumulation of 36 to 42 inches possible.”

I believe the scientific term for that kind of snowfall is “dumpage”.

[JWreno]

I ended up getting a 2nd permit for Cottonwood Pass on September 3rd and canceled my August 28th permit for Cottonwood Lakes. Cottonwood pass was my preferred entry point and the week later start date seems better and better as we continue to see the snow build. The Southern Sierra snowpack average is 257% as of March 12th. We will be exiting at South Lake. I suspect Mather pass may be the most snow covered of the passes on this trip.

We hiked from Cottonwood Pass to Yosemite Valley from August 13th to 30th, 2011 with a 3/4 zero day staying overnight at Muir Trail ranch. It was our sons birthday and we got a cabin with a queen bed and single, dinner, hot tub and access to a washing machine. Muir pass on the south end was the most challenging with much of the trail turned into a raging creek. We hardly saw snow on our 2008 and 214 JMT trips.

This will be our latest start date for a southern Sierra backpacking trip. I am looking forward to hiking mostly post Labor day weekend.

[texan]

The Leavitt Lake sensor is always fun because it gets such big numbers. Right now I think only one sensor shows a higher water equivalent - Farewell Gap. Unfortunetly the depth sensor is not working at Farewell Gap. Oddly, there are no manual surveys at Leavitt Lake so we never get a cpmparison between the manual numbers and the sensor like you get from some other locations. Usually there is some difference between the two, if only because the sensor is at one spot, while the manual survey measures the depth and water content at several locations along a line between two marked points and the averages of those numbers are the numbers published for that station.

The Leavitt lake sensor almost always has the most snow depth, I don't look as much as higher water equivalent. I I track that sensor because I go to Emigrant Wilderness a lot and want to get an idea how much snow is up there. The Farewell Gap sensor for snow depth hasn't worked all year to be my knowledge. Also the mineral king webcam which tells you the snow depth by the horse corral in the valley hasn't worked since Feb19,2023 it says 79 inches right now. I wonder how much snow there is now.

Texan

[Tom_H]

Southern Sierra currently at 277% of historical (1970-2022) median (though mean perhaps would be a better indicator):

https://engaging-data.com/california-snowpack-levels/

[Harlen]

The Eastern Sierra Avalanche Center's latest report includes some interesting data in graphic form comparing this year with other seasons, including 2016-17, and 2018-19. You have to click on Full Forecast to get to this graph, and some interesting photos of recent avalanche activity. I hope this link works, if not, I highly recommend using the E.S.A.C site for planning trips. They send a, Avalanche Forecast to your email every day.
https://mail.google.com/mail/u/0/#inbox ... bHJmTxMdGd

[Wandering Daisy]

The percent average figures shown on the CDEC website for northern, central, and southern Sierra do not show snow depths, which really are what we as backpackers are interested in. Even though the southern Sierra has a higher percent average, their "average" is less than central or northern Sierra. If you go to the snow sensor basin reports, you get a better idea of snow depth or water equivelant. For early season trips, the southeastern Sierra may still be the best bet for trail conditions even though higher elevations. The high elevations do result in slower melt. The danger in the northern Sierra is that more absolute snow also melts faster due to the lower elevations, making river crossings dangerous. The CDEC website also lists probable peak runoff dates, although it is for the lower gages on the major rivers. Probable peak runoff is earlier for lower elevation watersheds.

I have been surprised that more information on the big avalanche that covered 395 north of Lee Vining has not been in the news much. Right now getting to Lee Vining from the north is nearly impossible. Also, passes are likely to be late opening. So those of us in the north may have longer drives to east side trailheads early season. I would not be surprised if there will be some road damage to trailhead access. Another thing to consider when getting early season permits. Lots of impacts from this epic snow year are still in the works.

[c9h13no3]

Lots of impacts from this epic snow year are still in the works.

Exactly right. Damaged roads & bridges, trails obscured by avalanche debris, flooding, mud/rockslides. Even if the snow is gone on your desired route, this big winter is likely to affect your chosen route in other ways.