Thursday, February 23, 2012

[FEMA]

Homeland Security Threat Level: YELLOW (ELEVATED)

Significant National Weather:

West
Look for snow & lower elevation rain to develop over parts of the Northern Intermountain West, Northern Rockies and Central Great Basin this morning. Elsewhere will be sunny and dry, with highs in the mid to upper 70s across California and the Desert Southwest. Late tomorrow, a new Pacific system will begin to move onshore over the Pacific Northwest, producing more coastal rain & high elevation snow.
Midwest
A system moving from the Northern & Central Rockies will produce light snow over much of the Northern & Central Plains across to the Great Lakes this afternoon into tonight. Heavy snow is possible between the Upper & Middle Mississippi Valleys and Lower Peninsula of Michigan. Elsewhere, light to moderate rain will develop over the Middle Mississippi and Ohio Valleys today.
South
Rain and thunderstorms are expected over parts of the Tennessee Valley, and Southeastern U.S. throughout today, with a slight risk of severe thunderstorms threatening the lower Ohio & Tennessee Valleys into the Gulf States later this afternoon into tonight. Elsewhere, the Carolinas down through Florida should be mostly warm and dry, with temperatures 15-20 degrees above average across to southern/eastern Texas.
Northeast
A system moving from the Great Lakes will produce light to moderate rain over the coastal region of New England and snow over parts of the interior Northeast, mainly this morning. Temperatures will continue to be 15 to 20 degrees above average across the Mid-Atlantic today, with sunny to partly cloudy skies. By tomorrow, light rain and some thunderstorms will develop along and ahead of the associated cold front stretching from the Central Appalachians to the Mid-Atlantic.
Western Washington State Flood Event:

The heavy rains over western Washington are ending and rain amounts were less than anticipated. As a result, the upper reaches of the western Washington rivers crested early yesterday, and the lower reaches are cresting this morning as crests continue to move downstream. The Snoqualmie River at Carnation in King County (Seattle) crested yesterday at moderate flood stage and is receding, while the Snohomish River at Snohomish in Snohomish County (Everett) crested yesterday evening and has now receded below flood stage. Both the Green and White Rivers are anticipated to remain above the trigger points through this morning, February 23, 2012.
Planned dam releases from the Howard Hansen Dam will keep the Green River at Auburn in King County, WA at minor flood stage through Friday afternoon; and the White River is forecast to remain below flood stage for the period. Scouring of the Union Slough Levee along the Snohomish River near Everett, WA weakened two portions of the levee causing a loss of embankment material. The U.S. Army Corps of Engineers (USACE) Seattle District EOC is now activated at Level IV (Full Activation â 24/7 operations) and has deployed flood teams to the Snohomish (8 people), Green (5 people), and White (4 people) River basins. The Snohomish Flood Team is working 24 hours a day to reduce the risk of a levee breach by strengthening the levee with armor material.Â* The levee repair is approximately 40% complete; and work is anticipated to be completed this afternoon. No residences have been threatened. Meanwhile, the Green and White River teams are assessing levee and river conditions and providing feedback for regulation of the Howard Hansen and Mud Mountain Dams. There has been no request for FEMA assistance and none is anticipated.
The U.S. Army Corps of Engineers (USACE), Mississippi Valley Division, is identifying and developing communication strategies for the elevated threat in the Mississippi Riverâs flood risk reduction system brought about by 2011 flood damages. A USACE regional flood preparedness team is currently building on Mississippi River damage assessment information (which includes levees, reservoirs, channel stabilization and floodways). The massive 2011 flood damaged many structures, navigation channels and levees along the Mississippi River, leaving many in a state of vulnerability that raise concerns for increased risk of diminished performance, possible failure and potential for adverse consequence to their dependent communities, citizens and industry. The risks are being carefully assessed along with consideration for potential risk reduction measures that may be needed prior to the enactment of full repairs. In addition to the risk information above, select high-risk areas within the Mississippi River Valley will be modeled with a hypothetical major flood using historical data and the National Weather Service spring forecast, and then mapped to show potential inundation (e.g., inundation timing and depth). This regionally standardized inundation information will be extremely helpful for future interagency collaboration designed to enhance or improve preparation, mitigation and response to flooding emergencies.
Space Weather:

No space weather storms were observed for the past 24 hours and no space weather storms are predicted for the next 24 hours.Â*
Tropical Weather Outlook

No new activity (FEMA HQ)
Earthquake Activity

No new activity (FEMA HQ)
Disaster Declaration Activity

No new activity (FEMA HQ)


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