big river flows next week

[SSSdave]

From Sunday into next week the first good warm spell this spring is forecast to occur. With that warmth, it is likely many of our Sierra rivers will record their peak flows that are likely to build quickly over a few days. So will be interesting in reading how big those flows get. Every few years in May we get a sizeable warm rain that can also cause heavy runoff by melting snow even faster. For years I've monitored such events from the CDEC Daily Full Natural Flow page.

http://cdec.water.ca.gov/cgi-progs/stages/FNF" onclick="window.open(this.href);return false;

To watch any of these big flows one has to find a big river where there are no major dams above and to which one has access. In other words not still closed due to winter snow. That eliminates the San Joaquin, Tuolumne, Stanislaus, Kern, Mokelumne, American, Yuba, and Feather that have lots of dams.

Anywhere along SR140 into Yosemite, especially the big talus rapids above El Portal, can be impressive. Another spot I like is on the Kings just above Boyden Cave. Of course the Kings has a much larger basin and higher flows than the Merced.

[RoguePhotonic]

Melt! MEEEELLLLLLTTTTT I need to get past the snow fields!!! lol

[maverick]

Yes, melt, but not to fast, we do not want to get any major flooding.

[quentinc]

The South Fork of the Kern was a raging torrent this weekend (near Domelands).

[SSSdave]

CDEC was unusually slow in updating flows for last week however have now added several days of data up to the current midweek. (See the link in my opening post.) What it shows is with the heat last week, flows generally up and down the Sierra about doubled and have now decreased some with the waning temps.

The relative numbers between basins are a good measure of the amount of snow at specific ranges of elevations and exposures that is currently melting. The more area of those elevations in a basin, the greater the flows. The Tuolumne, San Joaquin, and Kings are all about the same as is often the case. Currently there are still high flows in the northern Sierra but because of their lower elevations, by late spring those numbers will tend to decrease below levels of the major southern Sierra rivers that have much more high elevation snows that melt last. Then in late summer the northern streams will have higher residual flows because their greater areas of sediments with volcanic geology release runoff more slowly than any of the southern more granitic areas.

[SSSdave]

The CDED full natural flow report for May 2011 is now posted in their Reports (see link below) and indeed that week of first warm weather produced the highest flows this year so far and I expect will hold up. Current flows are about half that volumne. Actually that period was not really all that warm but rather there was alot of snow that was ready to melt off.


http://cdec.water.ca.gov/cgi-progs/reports/FNF.201105