Flash Flood — Shelby, Alabama

2021-10-06 to 2021-10-07 · near Elvira, Shelby, Alabama

Event narrative

During the evening of the 6th, a north to south low-level boundary set up along the Interstate 65 corridor that became the focus for back-building thunderstorms and heavy rainfall. Over the course of just a few hours, a wide swath of 6-10 inches of rain occurred. Numerous roads became submerged and impassable. Countless water rescues were performed as travelers either became trapped by or drove into flood waters. Flood water several feet deep impacted parts of neighborhoods and townhomes. Several businesses were damaged by flooding. Extreme runoff also caused creeks and other waterways to rapidly swell. There was at least one report of a partial landslide in Pelham, sending dirt, rocks, and pine trees onto the road. A Flash Flood Watch had already been in place for a few days, highlighting the potential for flooding rainfall. A Flash Flood Warning was issued for north Shelby County early in the evening. At least four rounds of thunderstorms occurred, with ongoing and forecast impacts pushing the event to the highest level of flash flooding, a Flash Flood Emergency. Scanner traffic became nonstop with public calls for help and first responder needs for mutual aid and resources. Even after the rain subsided later in the evening hours,

flooding persisted for several more hours. Two deaths occurred when a vehicle was swept off the roadway and into a creek.

Wider weather episode

An upper level trough just west of the Mississippi River on October 3rd become stationary and evolved into a closed upper low by October 5th. The closed upper low remained nearly stationary for 48 hours and before finally lifting northward on October 7th. This system brought a variety of severe weather across Central Alabama over a five day period, including wind damage, large hail and extensive flash flooding. The most impactful flooding taking place during the evening of October 6th. Torrential, training rain and thunderstorms produced excessive rain totals across Blount, Shelby and Jefferson Counties and resulted in two fatalities in Shelby County.

View location on OpenStreetMap → (33.3370, -86.8830)

Source: NOAA Storm Events Database, event_id 990000. Narrative written by the NWS forecast office that issued the report.