Lakeshore Flood — Grand Isle, Vermont

2011-05-01 to 2011-05-31 · Grand Isle, Vermont

Event narrative

Record lake flood levels as well as several high wind, damaging waves and seiche events caused considerable and major flooding of lake shore roads, residents and businesses. The flooding began April 13th and ended June 18th.

Wider weather episode

Record Flooding occurred along the shores of Lake Champlain from mid-April to mid-June. NWS Flood Stages for the United States Geological Survey (USGS) gages on Lake Champlain at the ECHO Center in Burlington, VT and Rouses Point, NY are 100.0 feet and were surpassed on April 13th and finally receded below flood stage on June 18th.

Major flooding occurs with lake levels at or above 101.5 feet, which were surpassed from April 27th ' June 8th as the lake level exceeded its flood stage of 100 feet from April 13th to June 18th. Further, the lake level exceeded it's previous flood of record of 102.1 feet on April 28th and crested at 103.26 feet on May 6th, before eventually receding below the previous record on June 5th.

In addition, strong south to southeast winds of 25 to 35 mph (greater at times) caused extensive damage due to 3 to 5 foot wave action as well as 0.5-1 foot seiches on windward facing shores (New York and Vermont). These episodes occurred on April 23rd, May 2nd, May 22-23rd and June 1st. North to northwest winds of 20 to 30 mph caused extensive damage due to 2 to 4 foot waves and seiches around an half foot on windward shorelines (Vermont) on May 9-10th and June 1st-2nd.

These record lake levels were attributed to a combination of a 125-150 percent of normal winter snowfall, subsequent melting of that snow pack and an abnormally wet meteorological spring (March, April and May). Normal precipitation for meteorological spring within the Lake Champlain basin is 8.5-10 inches, yet observed precipitation was 16 to 26 inches (> 200 percent).

Serious and extensive flooding to dozens of lake shore roads, 500-1000 houses and dozens of businesses. In addition, the periodic closing of the Lake Champlain ferry from Grand Isle, Vermont to Plattsburgh, New York and the delayed opening of two additional ferry crossings.

Damage estimates will be incorporated into the May storm data, representing the crest of the flood waters, thus the time of the most significant impact and damage.

Source: NOAA Storm Events Database, event_id 309393. Narrative written by the NWS forecast office that issued the report.