The March Sierra Nevada Snow Survey

[tgtaylor]

"With all the media
hype about the huge winter let’s put it into perspective. Many of the High
Sierra March 1 snow surveys from 2017 were the largest ever measured on the
date. The 2019 measurements have averaged just about 60% of those measured
in 2017. In 2017 March snowfall was lackluster so peak snowpack April 1 was
less then the record years of ‘69 and ‘83. What happens this month will be
decisive as to how the snow year actually ends up but as of now the High
Sierra is a bit over half of what it was in 2017." - John Ditti, California State Snow Surveyor.

Thomas

[Drew Wiley]

The winter record ever measured at mid-elevation (about 7000 ft) was over 90 feet! in the 1890's. This was likely quite accurately measured for the Donner area due to both the massive commercial ice business on Donner Lk as well as the nearby railroad. It precedes the current office of Snow Survey, but it wasn't necessarily an uncommon depth back then. John Muir got his idea of Sierra glaciation from extant glaciers on Merced Pk, which were already long gone when I was born. In fact, that was the world record for annual snowfall until modern remote monitoring equipment was installed in southern coastal Alaska. But 90 ft at 7000 was probably less that what fell higher up, where it wasn't measured. Max snow depth typically accumulates around 9000 ft. Drifts can be far deeper. Single month averages don't tell the whole story. But this is one March that is probably just too avalanche-prone for realistic backcountry ski travel.

[Willie]

How do they get the snow to fill out a survey form? North Dakota snow can't do it...

[Vaughn]

It sounds like we are at 'average' annual snow fall in the Sierra for up to this date...which as Drew points out, is dependent on what one wishes to consider 'average'.

[Drew Wiley]

Snow levels allegedly peaked during the "little ice age" of the 1700's. Then the Industrial Revolution came and started gradually raising global temp, though nowhere near the rate as now. But when I was growing up in the Sierra there were still lots of cirque glaciers around. Now just a few. And heavy snow years seemed a lot snowier than now. This particular year would just be average, not heavy snowfall like it seems after a decade of drought more often than not. But it will probably be a bad mosquito season until August.

[EarlJam]

The National Weather Service just posted a hydrologic outlook, predicting flooding this year in the Cascades and Sierra Nevada from snowmelt.

RISK OF CALIFORNIA FLOODING DURING THE SNOWMELT SEASON IS ELEVATED
THIS YEAR FOR MUCH OF THE CASCADES AND SIERRA NEVADA. FLOOD
CONVEYANCE SYSTEMS BELOW MAJOR RESERVOIRS IN THE SAN JOAQUIN WILL
BE UNDER ADDITIONAL STRESS THROUGHOUT THE SPRING. FLOODING
ANYWHERE IN THE STATE COULD ALSO RESULT FROM HEAVY RAINFALL, OR
THE COMBINATION OF RAIN AND SNOWMELT AT ANY TIME DURING THE
SPRING. REFER TO THE LONG RANGE OUTLOOK PRODUCT FOR FLOOD
EXCEEDANCE PROBABILITIES AT PARTICULAR LOCATIONS FOR THE MARCH
THROUGH MAY PERIOD. FOR SHORT TERM HYDROLOGIC FORECASTS AND
GENERAL WATER RESOURCE INFORMATION, PLEASE SEE THE CNRFC HOMEPAGE
AT: HTTP://WWW.CNRFC.NOAA.GOV.

https://forecast.weather.gov/showsigwx.php?warnzone=CAZ554&warncounty=CAC059&firewxzone=CAZ554&local_place1=Fullerton%20Municipal%20CA&product1=Hydrologic+Outlook&lat=33.872&lon=-117.9806#.XIHGs3dFyUk

[MikeH]

We've had a LOT of rain, so the ground at the lower elevations is soaked. Most of the storms this year have come from the northwest, rather than the southwest, so they are colder with much less moisture. So the snowpack will have less water. But, because the lower elevation ground is so saturated from all the rain, it can't absorb any more water.. so the runoff will be greater. It all depends on whether it stays cold, with the snow melting slower, or if it warms up...

[Two23]

Our problem is all the snow sitting on top of ground that's frozen three feet down. All the melt is going to have to run off. The few waterfalls in the region should be spectacular though!


Kent in SD

[Drew Wiley]

Now most of the Sierra Nevada is at around 150% of average snowpack, including the higher portions in the southern part of the range. That equates to potential avalanches presently, a lot dangerous stream runoff in June, and an especially bad skeeter season in July. After that, we might be treated to "Spring" bloom and fall color simultaneously in the parts of the high country around Sept. But I've seen considerably heavier snow years numerous times in the past. What I still need to research is snow conditions in Wyoming, because I'm headed to the Wind River Range first, in August.

[Leszek Vogt]

I was just reading an article on Mamomoth Lakes area and some places snow packed to 50' (don't shoot me, but that's what it said)....it sounds rather incredible, but I have a feeling that this may cause some serious floods....certainly massive runoff. Hmmm, avalanches might be part of the equation. I think it would be good idea to take a kayak along, eh ?

Les

[Willie]

With a good amount of snow will the runoff be enough to raise the level of Mono Lake much?

[Vaughn]

From the recent Mono Lake Committee Newsletter:

On October 1, 2018, Mono Lake was
at the same level it was on October
1, 2017. The lake level dropped lower
through the end of 2018, only to catch
up again in early February 2019. It is
unusual for winter lake levels to track so
similarly, since there is usually a lot more
variability from year to year. However,
this year by late February the level had
already exceeded the April 1, 2018 level
and is expected to continue rising.

Mono Lake—at 6381.85 feet above
sea level in late February—is still about
2 feet lower than it was at the beginning
of the 2012–2016 drought. Currently,
Mono Lake has about 10 vertical feet
to go before it reaches the management
level of 6392 feet above sea level.

[John Kasaian]

One good thing is that all that heavy snow will bring down some of the dangerous beetle kill trees, especially in places where chain saws are forbidden.

[Drew Wiley]

I my lifetime, some places have had snow has packed over 200 ft, Les; and I'm not counting glaciers. As I mentioned somewhere earlier, the greatest amount of recorded snowfall in a Winter season was over 90 ft in the 1890's; but that was at mid-elevation, not higher up where it could have been considerably deeper if anyone had measured it back then - a potentially suicidal mission. But yes, drifts and other forms of pileup factor in to cumulative depth. That's why the official snow surveys are always done out in the middle of big flat meadows, where actual snowfall is the predominant factor. Kayaking season depends on the stream they're trying to run. It can involve a lot of strenuous backpacking including carrying the kayaks themselves, plus typically a lot of technical rope work getting over waterfalls or around cliffs that can't be run directly. Some river sections seem to require more time lowering the kayaks and other gear on ropes than actually in the water. Floods are manmade. I should know better than most. So does John K. Both our parents worked on the dam that was the start of the whole Central Valley Project, intended for both irrigation water and flood control. My dad was in charge of the Friant-Kern Canal. Much of the Valley that is now arid was once vast seasonal flood plain. Ships came all the way from SF Bay to Tulare Lake way down by Bakersfield to harvest turtles for SF gold rush restaurants. Thousands of Indians once lived on the shores of Tulare Lake, which is now white alkali powder most years. But there is only so much water you can keep behind a dam. More dams don't necessarily help. Water release is important for both hydroelectric power (the primary function of all the dams upstream), and for agricultural use. That's why they survey the snow to see how much to empty out in advance of the June melt. If someone is stupid enough to buy a house on a susceptible riverbed or floodplain, which thousands of people obviously are, there will be an equal number of unscrupulous developers willing to accommodate them and take their money. That's why I call it a manmade problem. But what is even more fascinating about those floodplains in how they behaved back in the Ice Ages. Vast herds of big animals - camels, horses, mastodons, mammoths, etc - would be feeding in those areas, and then suddenly an ice dam would burst on some glacier way upstream and they'd all get instantly buried. There are fossils beds all over the place if you dig deep enough, which did happen during canal work. But alas, the local museum north of Madera seems to have suddenly closed due to lack of funding. They had a short faced bear skeleton in there that would have made you think twice about wanting to be a hunter armed with a spear thrower back then, 50% bigger than any living bear species. They also had a Harlan's ground sloth skeleton as big as a backhoe, with claws a foot long, which was the smallest species of sloth roaming around at that time! But it had a tiny brain that was probably well programmed with a complete lack of patience for any bear that did presume to take a bite out of its backside. Their hide was embedded with bony plate armor.

[John Kasaian]

This was reported today---162% of normal at Phillips Station near HWY 50
https://www.kcra.com/article/sierra-snowpack-162-percent-of-average-as-runoff-begins/27023799

[tgtaylor]

And it's still raining!

Thomas

[Drew Wiley]

It's a bit of an unusual year in that the whole length of the range (northern, middle, and the higher southern) is now fairly consistent at right around 160% of statistical "normal". Ordinarily, there's a fair amount of discrepancy between the northern and southern portions due both to different prevailing storm directions and different altitudes. So June will be dicey with stream crossings, and July truly a vampire blood letting under squadrons of mosquitoes. But probably pretty nice after that, though an ice axe might still be helpful for especially high off-trail passes. Meanwhile, the snow reports in the nothern Rockies, specifically Wyoming, vary a bit from between 10% over to 10% under average conditions. I expect a fabulous wildflower display here on the coast, especially Pt Reyes, well through June. Poppies are already common here on the East Bay. I'd expect a pretty good swath of them at the mid elevations of Mt Diablo in a month or so. Of course, there are a lot of other flower species popping up too, if you'll excuse the pun. Unfortunately, prime flower season in the high Sierra coincides with peak mosquito season, since they're predominantly nectar seekers, but prefer blood when they can get it. My advice is, bring along a fair-skinned, blonde, blue-eyed friend and ask then to wear bright yellow clothing and lots of perfume. That way, you won't get many bites yourself.

[tgtaylor]

The 2019 snow pack is similar to the 2011 and 2017 snow pack: https://cdec.water.ca.gov/snowapp/swcchart.action. In 2011 Tioga road opened on June 18th and in 2017 on June 29th. https://www.nps.gov/yose/planyourvisit/tiogaopen.htm. However Elizabeth Wenk, author of a popular guide to hiking the John Muir Trail https://www.amazon.com/John-Muir-Trail-essential-Americas/dp/0899974368 points out that the 2019 snow is concentrated considerably
lower than the 2017 snow was:

It's an above-average year for sure but probably won't linger as long as
2017 at the altitudes where we hike and which comprise the watersheds above
our more problematic crossings. So unless the melt is delayed or there is
lots of new April-June snowfall we should see June-July easier in 2019 than
the very challenging 2017

So at this point it looks like Tioga road will open mid to late June.

Thomas

[karl french]

Plowing typically starts on April 15th. I'm looking forward to the pass opening.