Wednesday, December 22, 2010

Flowing Down The Rivers

Here in southern Utah we have had an unusually large amount of rain over the past 5 days along with flooding over the past 3 days due to the presence of the Pineapple Express weather system (see previous post for brief details).  

The interesting thing about all this water showing up essentially all at once is the amount flowing in the two main rivers near St. George:  the Virgin and the Santa Clara.  The usually tiny Santa Clara River flows into the bigger Virgin River in the Bloomington area of St. George city.  A good portion of our total average annual rainfall (8-12 inches) will have fallen by the time this system passes off to the east.  

I wasn't able to get ever to Zion today to get any photos  - hopefully tomorrow.  
The North Fork of the Virgin River  flows through the main Zion Canyon.
The typical flow of the North Fork near Springdale (just outside Zion NP) is 150 cubic feet per second (cfs). 
On Tuesday 12/21 @ 10:00 AM, the North Fork peaked at 5340 cfs.
At 6:00 PM on Wed. 12/22 the peak flow was expected to be 4000 cfs.

Downstream (from here involving the flow of both the North and East Forks)  12 miles or so, at the town of Virgin, peak flow on Tues. 12/21 was 8500 cfs.

Downstream ≈ 8 miles further at Hurricane, at 10:00 AM Wed. 12/22 the Virgin River peaked @ 5391 cfs.  It is forecast to peak at midnight 12/23 Thursday morning at 9000 cfs.
The typical flow at Hurricane, due (I’m guessing here) to irrigation withdrawal, is 70 cfs.

Santa Clara River flow is usually 6 cfs
Santa Clara River takes out the bike trail but leaves the bridge
There is also the Santa Clara River  (just barely a creek most of the year, or a slightly wide stream…):
The typical flow of the Santa Clara River is 6 cfs (See?  I told you!).
Last night the flow was ≈2300 cfs. 
At 10:00 PM Wed. 12/22 it is predicted to be ≈ 2500 cfs.

Virgin River below the confluence - bike trail is washed out
I mentioned earlier that the usually tiny Santa Clara River flows into the bigger Virgin River in the Bloomington area of St. George city.  
Tuesday night 12/21 the peak flow below the confluence was 15,822 cfs.
The peak is predicted to be ≈ 13,000 cfs at 1:00 AM Thursday 12/23.

As I drove around town today and stopped to watch the river, I was overcome by the power of the water.  And so it really comes as no surprise that, over a few million years, the Virgin River is capable of carving Zion Canyon.

Flood warnings continue to be
posted through 3:00 PM Thursday afternoon 12/23.

Stats courtesy of
Virgin River near Bloomington

I won't be bicycling here anytime soon

1 comment:

  1. Ah yes, the power of water. So soft as to wash in yet powerful enough to change a landscape. Be real careful out there. I imagine our wash is flowing this morning after a full night of rain. Looks to clearing up soon.

    Happy Holidays to you!