Late-afternoon update: Flooding predictions in Delaware and Ulster County

Within the last hour, we received press releases from emergency coordinators about flooding predictions for tonight and tomorrow. Here's the Delaware County press release:

The Delaware County Emergency Operations Center was opened at 1300 hours today in preparation for the impending rain/flood event.

The Pepacton reservoir is expected to begin spilling at 8:00 PM March 11th with a spill of 7,500 at its peak.

The Cannonsville Reservoir is expected to begin spilling at 8:00 AM March 11th with a spill of 13,000 at its peak.

The Susquehanna River is expected to crest between 13.5’ and 14.5’ at Unadilla and 19’ – 21’ at Bainbridge. This will create moderate flooding in low lying areas of Sidney.

The West Branch of the Delaware River is expected to crest at 13.0’ in Walton which will create minor to low end moderate flooding concerns between the Village of Delhi and the Village of Walton.

Small streams may rise fast and create flash flooding issues throughout Delaware County later this evening and overnight.

There are no road closures reported at this time.

The public should be aware of the impending weather situation and make preparations if they live in low lying or flood prone areas.

When driving citizens should not drive through flooded roadways or bridges. Turn around don’t drown.

And Ulster County:

Very little change in the forecast from yesterday. The National Weather Service office in Albany did not hold a conference call today, but here is information from a variety of sources:

Rain - still expecting a widespread 2-3.5" event with locally higher amounts (4 inch range)

Flood watches / warnings: a flood watch remains in effect for the entire County, a flood warning has already been issued for the Wallkill River by the NWS office in Upton. Look for many flood warning updates from NWS throughout the night into the morning.  The best way to receive these is through NY Alert

The Advanced Hydrologic Prediction Center has forecast the following crests: Upper Esopus at Coldbrook: 15.2 feet at 1 PM tomorrow (flood stage is 11'); Lower Esopus at Mt Marion: 21.4 feet at 1 PM tomorrow (flood stage is 20'); Rondout at Rosendale: 20 feet at 7 PM tomorrow (flood stage is 18'); and the Wallkill at Gardiner 18.9' at 7 PM tomorrow (flood stage is 13').

***I caution you on how much faith to put in the AHAPS predictions - they are often off in both timing and
  height.***

Temperatures will be in the lower 50's on Friday and upper 40s on Saturday. This will cause a significant melting of whatever snow doesn't get washed away by the rain.

Today's reservoir levels courtesy of DEP: Rondout 96.2% today (this is expected to spill); Ashokan 83.7% today (there is 14 billion gallons of water in the snow pack with a nearly 21 billion gallon buffer in the reservoir - spill will be determined by both how much snow melts and how much rain is received in the watershed). The waste channel at the Ashokan has been running at 600 MGD (million gallons per day) but this will cease once the Mt Marion gauge reaches 17' (so as not to create more serious flooding).

A wind advisory is in effect for Western Ulster through 6 AM tomorrow.

If assistance is needed, please don't hesitate to call.
Art

Arthur R. Snyder
Ulster County Emergency Communications/Emergency Management
238 Golden Hill Lane
Kingston, NY 12401
Phone: 845-331-7000
Fax: 845 331-1738
E-mail: [email protected]

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