Friday, May 23, 2008

Flaky weather

On Tuesday, temperatures were in the 80's Fahrenheit. It cooled off Wednesday, and today, it did this:



It started snowing on Wednesday in the high country, which may explain the hydrograph for the Animas River:



(Image source: USGS Water Watch)

I was talking to one of my colleagues about the daily peaks: notice that they were always before noon. (Compare it to the gage height graph from Ouray, posted at Geology Happens for this month's Accretionary Wedge.) And the peak discharge was on Wednesday, when it started cooling off.

My colleague reminded me that the Animas has a long way to go from the high country. Nobody rafts all the way from Silverton to Durango - there's an impossible-to-run section deep in the canyon, clogged with logs, certain death to even the most skilled kayaker - but he had a good sense of how long it takes to get through town at high water. It made sense that the water might take around 16 to 20 hours to make it down to Durango. That would explain the morning peaks, and also the highest discharge on the day it started to cool.

And the diurnal fluctuations have disappeared. The snow is currently accumulating again, up to a foot and a half of snow predicted in the high country this weekend. I hope for the sake of the soon-to-arrive field camps that it melts quickly. Though the water managers may have different wishes.

2 comments:

Old Bogus said...

On a longer scale, the Sangre de Cristos are cycling between white and rock colors on a biweekly basis. They get the snow your San Juans don't extract from weather systems and feed the Rio Grande and Arkansas Rivers. Which melts off revealing the above-timberline rock.

The river flow at Parkdale on the Arkansas follows a similar pattern to the Animas, just with a different peak time. http://nwis.waterdata.usgs.gov/nwis/uv?07094500

coconino said...

I hope it melts quickly for your field camp, too, but not so quickly that it causes downstream flooding. Along the San Juan and the Animas in New Mexico, there are folks who live very close to the river's edge; high water above the flood stage could cause significant damage.