High Sierra Topix

I thought this might be a good place to leave this.


Below are the April 1 SWE (snow water equivalent) for the snow courses measured along the High Sierra from the Merced River south. These courses have been measured exactly the same way in the same place since the 1930’s. The courses are measured 2-5 times a year at the end of each winter month. April 1 is known as the holy grail of snow course measurement as it usually marks the peak sample date. Yes, the snow can peak after that point but most commonly there is less water on the ground by May 1 than April 1. For comparison purposes In the case of post April peaks I used the higher number.
I put together this data solely for the purpose of history, do with it what you will. I have included some spot checks north of the Merced to Sonora Pass as that is where the High Sierra, for me, begins. I have included the years 1969, 1983 as the comparison years as those are the standout years since 1930. For the Owens I included the eastside anomaly of 2017. 1952 did not make it into the top five in the High Sierra. As you will see from the numbers this year, 2023, stands out remarkably to the far south (Kern) as well as the upper elevations to Sonora Pass. All numbers a inches of SWE. Formatting is a bit goofed up here, but I guess you can figure it out.

2023. 1969. 1983
Sonora Pass. 72.5. 51.4. 51.6
Bond Pass. 86.5. 85.3. 86.2
Tuolumne Mdw. 62.5. 50.6. 52.3
Dana Mdw. 73. 58. 62
Rafferty cr. 76. 58.8. 59.2

MERCED RIVER April 1 SWE
evidence of how 2023 and 1969 drop off in the north. I don’t know what to say about the Snow Flat anomaly.

2023. 1969. 1983 Snow Flat. 109.4. 88.2. 95.9
Ostrander. 80. 70.2. 90
Tenaya Lk. 77.5. 65.8. 77.9
Peregoy Mdw. 61.5. 68.7. 73.5

Basin wide April 1 ave


SAN JOAQUIN RIVER April 1 SWE
Unfortunately eleven courses weren’t measured this year, most were low elevation with the unfortunate exception of Gem Pass

2023. 1969. 1983
Paiute Pass. 74. 80.9. 73.4
Emerald Lk. 63.5. 70.9. 64.5
Heart Lk. 60.5. 60.8. 56.3
Volcanic Knob. 64.5. 63. 58.1
Rose Marie. 66. 61.7. 60.8
Colby Mdw. 51.5. 50.3. 47.2
Agnew Pass. 92. 65.6. 62.7
Kaiser Pass. 95.5. 81.9. 78.4
Dutch Lk. 61.5. 62.1. 61
Coyote Lk. 83.5. 75.8. 66.6
Cora Lk. NA. 80. 85.3
Nellie Lk. 81.5. 79.8. 90.9
Florence Lk. 25.5. 30.5. 25.6
Huntington Lk. 44. 53.1. 55.2
Pioneer Basin. 79. 71. 65.3
Thomas Edison. 45. 46..4. 40.9

Basin wide April 1 ave. 254%

KINGS RIVER 2023 April 1 SWE
Still huge, showing additional drop off to north and low elevation

2023. 1969. 1983
Bishop Pass. 77*. 78.4. 70.1. 3/25 likely +1-2” by 4/1
Blackcap Basin. 79. 68.6. 73.3
Burnt Corral. 88. 78.8. 78
Beard Mdw. 79. 74. 70
Rowell Mdw. 81.5. 74.9. 61.2
Woodchuck Mdw. 78. 81.3. 70.3
Round Corral. 87. 88. 79.6
Helms Mdw. 74. 65.8. 59.8
Long Mdw. 77.5. 69.2. 62.2
Statum Mdw. 88. 83.3. 75.2
Post Corral. 70. 69.4. 58
Big Mdw. 60. 78.2. 67.3
Horse Corral. 43.5. 57.7. 44.2
Fred Mdw. 55.5. 57.7. 55.4
Charlotte Ridge. 75.5. 51.2. 52.9
Bullfrog Lk. 72.5. 55.2. 57.4
Dobsons Mdw. 78. 73.3. 64

Basin wide average of April 1 261%


KERN RIVER 2023 April 1 SWE
the numbers are truly impressive and represent across the largest SWE (snow water equivalent) ever measured in this part of the High Sierra (dating back to 1930).The numbers show how, like 1969, the storms of 2023 were weighed to the south.

2023. 1969. 1983.
Bighorn. 67.5. 55.3. 48.9
Cottonwood pass. 46.5. 41.1. 36.4
Siberian Outpost. 57.5. 48.4. 45
Crabtree 57. 48.5. 45.3
Guyot flat 58.5. 50.6. 49.2
Tyndall cr. 60.5. 48.6. 43.7
Rock cr. 56.5. 45.8. 44.7
Big Whitney Mdw. 52.5. 45. 38.7
Round Mdw. 40. 69.8. 68
Ramshaw Mdw. 40.5. 38.1. 33.2
Little Whitney Mdw. 50.5. 46.1. 37.6
Bonita. 44.5. 50.2. 42.2
Casa Vieja Mdw. 58.5. 61.4. 48.1
Quinn RS. 65. 59.8. 52.1
Beach Mdw. 32. 36.8. 30.6
Sandy Mdw. 55. 46.3. 46.9

Basin wide average, 332% of April 1


OWENS RIVER April 1 SWE (snow water equivalent)
Could be time to resurrect the Mollie Stevens on Owens Lake.
Some fresh numbers from the Owens, all but two courses measured. Mammoth Pass is quite astonishing. Some really remarkable numbers on a few courses and in fact record breaking

2023. 1969. 1983. 2017
Mammoth 8000’ 54.5. 47.4. 45.8. 35.5
Rock cr 3. 42.5. 39.3. 30.4 35
Rock cr 2. 33. 32.6. 24.2. 14
Rock cr 1. 31.5. 28.6. 20.1. 21.0
Bishop Lk. 58. 48.1. 47.0. 50
Minaret 2. 80.5. 63. 64. 59.5
Mammoth pass. 104.5. 86.5. 85. 82
Cottonwood Lk. 40.5. 39.5. 30.4. 29
Sawmill 51. 49.3. 36.6. 40
North Lk. 38. 35.5. 22.4. 27
East Paiute. 48. 40.7. 38.6. 36.5
Big Pine 3. NA. 65.2. 32.8. 38
Big Pine 2. 44. 50.4. 28.4. 28.5

Water basin wide 311% of average April 1

depending on your measure of central tendency (mean, median, mode), if the "average" peak is april 1, about half of years' peak will come before that date, about half after. averages can be as misleading as they are informative. nevertheless, I think we'll have the biggest snowpack south of Sonora pass in the last century, maybe longer. very telling that in Tuolumne Meadows, where they've been doing manual measurements since 1930, this april 1 has set the record. for snow water equivalent, if not depth. remote sensors are reporting more SNW in southern sierra today than on april 1.

The averages are not mine but that of DWR. And no, the average has nothing to do with whether or not the pack peaks before or after April 1, the average is the mean of April 1 measurements from the years 1991 to 2020. This allows for quick basin to basin, year to year, comparison. Pretty simple really. That’s why they have used these numbers for almost 100 years to forecast the most valuable resource in the most wealthy state in the union, so im guessing not all that misleading if you know how to read them. BTW, over half the courses listed are from around 1930, not just Tuolumne. Others are from the 1940s. Yes, we have the most SWE ever recorded in the High Sierra, depth is rather irrelevant once the snow settles, that was the point of the post. The data gathering was to compare this year to the previous large years. BTW, I’d trust SnoTel about as much as a snow bridge in August this year. You’re welcome.

just wild. thank you for parsing this for us.

Thanks for posting this. It shows how much snow there really is. The manual way of checking SWE is still the most reliable way to check. I would have liked to know what Leavitt Lake and Farewell Gap was but it looks like there isn't a manual measurement, only snow sensor. Thanks again for sharing this valuable data.

Texan

Thanks for posting this.

I'm honestly baffled about when to take my Sierra trip this year, and where. I'm keeping an eye the snow and river monitors through June and then i'll likely make a decision sometime in July. Now that I live in PA I only get one trip a year. I missed the spectacular snow in the San Gabriels out where my old place was.

In no particular order:

-mosquito season is going to be baffling
-wildflowers should be spectacular
-any route that requires a drive on a forest road is concerning to me if there's a warm spring and high runoff. My first choice route is from Isberg TH, but Beasore Rd is already a mess from the Creek Fire burn scar and they're replacing a bridge this summer. There's forest road routes around the bridge in question, but who knows what state they'll be in. Many are in the burn scar. I'll be calling ahead.
-my current plan is for the usual late July, but for the first time ever i'll probably be bringing microspikes and an ice axe for any xc passes.

It must be an amazing year to be touring into the Sierra to take these measurements. I think I envy the survey crews, but this year must've been a challenge! Thanks for putting this data together and sharing with us John. I didn't realize till I saw this that the southern Sierra has received so much snow! I have been trying to pick the right time to get in there, and it's been hard, but now I realize that we can extend our ski touring season well into summer. I may get to ski all over the upper Kern July?! I suppose there will be record-setting sun-cups to go with all of this snow.

Anyhow, I echo the rest of us here who are grateful for this great contribution of yours. Cheers, Ian.

Humphreys Basin in mid-June, 2017:

Yes! thanks for posting this. It would be interesting (and a lot of work) to make similar charts for Memorial Day. I think you would have to do this with different data points unless the snow course data points also include instrumented snow depth. Is it correct that April 1 is the last snow course measurement? Obviously 2023 would have to be added as the melt happens this year. Northern California data would be useful too, for those of us who are trying to figure out where to go this year on early season trips.

What you presented shows that lower elevation does not always equal less snow.

It has been windy too, so I suspect there will be a lot of snow cornices where least expected.

Wandering Daisy. Most of the courses in the “High Sierra” are last measured on May 1. On big years, we also measure June 1, my guess is that this will be called for again this year. Also, sampling does include snow depth.

So you got my interest. June 1 is sporadic but here’s a sampling depth/SWE

Crabtree 1969 40/23. 1983 67/34
Cottonwood pass 1969 32/17. 1983 54/28. 2017 30/16
Bighorn. 1969 67/38. 2017 67/39
Bishop Pass 1969 113/62. 2917 116/67
Blackcap 1995 111/67. 1978 104/64. 1998 103/53. 2011 90/49. 2019. 81/47

Bishop Pass and Blackcap numbers are pretty impressive!

I looked back at what I did in 2017. First two trips were in Yosemite. Snow on the way up to Mt Watkins. Second trip a week later up to Merced Lake, all snow had melted but water everywhere, lots of wading on flooded trails. A month later I went to Pioneer Basin, which is one of the high country areas that melts fairly early and Mono Pass was solid snow, patchy snow mid-level lakes and solid snow upper lakes. By end of July there still was plenty of snow in Granite Park; high water was more of an issue for me than snow; I barely got across Pine Creek. I do not recall if the spring temperatures were unusual, either warmer or colder than normal. For now I am guessing similar conditions for 2023.