Flood — Danville (c), Virginia

2018-10-11 to 2018-10-13 · near (kdan)danville Regional Airport, Danville (c), Virginia

Event narrative

The Dan River at Danville (DVLV2) crested at 30.01 feet (50300 cfs) on the evening of the 11th. Major flood stage is 25.5 feet. It was the highest reading at the current gage location since USGS records began in 1996 beating the previous record of 28.65 feet set on September 6, 1996 with the remains of Hurricane Fran. In terms of flood frequency (using regional regression equations) it fell between a 25-and 50-year event (0.04-0.02 annual chance flood). Significant flooding took place in Danville.

Wider weather episode

Hurricane Michael made landfall along the Florida panhandle as major hurricane (Category 4 on the Saffir-Simpson scale) on Wednesday afternoon, October 10th, 2018, then tracked northeastward with the northern portion of the storm circulation tracking across portions of Southside, Virginia Thursday afternoon, the 11th. A deep flow of tropical moisture into the Appalachians and central mid Atlantic region ahead of the storm began to generate excessive rainfall across portions of the region as early as Wednesday evening, mainly along the Interstate 77 corridor, causing some degree of flash flooding and otherwise saturating the ground even before the arrival of the rainfall directly associated with Michael.

As the storm circulation approached on Thursday, a cold front moving in from the west and interacted with the storm and enhanced rainfall especially east of Interstate 81. Widespread rainfall amounts of 4 to 8 inches were reported, along with local amounts over 10 inches, mainly from the mountains of North Carolina up through Southside Virginia. This resulted in significant flash flooding with flash flood emergencies issued for the city of Roanoke, as well as Roanoke County, and southern Pittsylvania county including the city of Danville. Unfortunately, there were five fatalities as vehicles were swept away by flash flood waters in Pittsylvania County, Danville, and Charlotte County, Virginia.

The massive volume of water also then generated rapid rises on rivers including the New, Roanoke, and Dan. Major flooding was reported at several river gage locations along with a couple of record crests. There were a few landslides reported as well, blocking roads and in one case destroying a shed.

In addition, as the northern portion of the storm circulation moved across the Piedmont, bands of heavier rains/convection developed and mixed strong winds down to the surface. Many trees were blown down in the water logged soil especially across Pittsylvania, Halifax and Charlotte counties of Virginia where rainfall was heaviest. Despite some initial reports of tornado sightings, damage surveys revealed no conclusive evidence of tornadic circulations and judged damage was caused by straight line winds.

View location on OpenStreetMap → (36.5543, -79.3497)

Source: NOAA Storm Events Database, event_id 788635. Narrative written by the NWS forecast office that issued the report.