California Applications Program / California Climate Change Center

Yosemite Valley Flooding: 17 May 2005

Information on the flooding after the time-lapse of Sentinel Dome below

Mike Dettinger has provided the webcam views of Half Dome from near Sentinel Dome at noon for May 17 through June 7 (since the day after the May floods), strung together into an animated gif file (note May 31-June 2 images are missing). (Refresh/reload this page to repeat the animation; if it does not refresh/reload, try holding down the shift key while you click on refresh/reload.) At Lower Kibby Ridge (6700'), snow-water content has declined by about 18 inches since May 20 (to May 24). That may be 3 feet or more of snow-depth loss. Notice how far down the snowpack in the foreground has fallen, but also how hard it is to see changes in the background snow cover. On Half Dome and a bit below Clouds Rest area you can see depletion in the snowcover.
Click here for an animated gif every 15 minutes of daylight for May 20-24 (large file!). You can watch the bush in the foreground emerge, see a squirrel run by, and watch the clouds and shadows wander by. You can also see that the snowpack-depth decline stops each night and then recommences in the mornings.

Time lapse view of Half Dome from near Sentinel Dome
(current live image at:

Links to news articles:
Fresno Bee (17 May 2005; 9:01am): "Floods hit Yosemite Valley"
Sacramento Bee (17 May 2005; 2:15am): "Flood shuts Yosemite Valley"
High Merced River Flow: updated 17 May 2005

16 May 2005 - Morning view of Half Dome from near Sentinel Dome
(current live image at:
Mike Dettinger has alerted us to the surge of water in the Merced River today - 16 May 2005. The morning picture of Half Dome (as seen from near Sentinel Dome) in Yosemite National Park is shown to the left. The clouds appear patchy but reports have it that it was raining perhaps to 8000 feet this morning. From Jim Roche (NPS), via Jessica Lundquist: "I just spoke to Jim Roche. They're having a rain-on-snow event right now with the snowline up around 8500 to 9000 ft. The entire valley is flooding across the meadows adjacent to the Merced. If conditions stay warm this week and snow keeps melting, the park is expecting floods to potentially get worse -- they're actually keeping people out of several areas." Mike's plot (to the right) shows the flow at Happy Isles so far this year (through 15 May 2005). For the historical perspective, click here to see the flow for every day since October 1915 (updated 17 May 2005). The peak (daily) flows above about 4000 cfs are highlighted and categorized. Notice that the biggest floods at Happy Isles have been winter (almost all December and January) flows. Then come a second tier of spring and summer floods, the biggest of which seem to cluster in the ca. 4000-5000 cfs range that we find ourselves in today. So today is a big event, but falls in a "population" of "warm" floods that appear scattered through the record. As an aside, the Merced is one of the western rivers that has been trending towards more frequent occasions when the peak daily flow in the year occurs on wet days (like today) rather than on clear (warm) days. A recent New York Times article about the rushing waters in Yosemite: "Yosemite Drapes Itself in Its Splendid Liquid Veils, and Preens".

Last update: 20 June 2005