US: Adverse weather forecast across the Ohio Valley Region through at least early Aug. 2 /update 4

Event

Rounds of heavy rainfall accompanied by possible thunderstorms are forecast across parts of the Ohio Valley Region through at least early Aug. 2.

Heavy rainfall since late July 27 triggered severe flooding and associated disruptions in parts of eastern Kentucky. As of late July 31, authorities have confirmed at least 28 fatalities across the state; the death toll is likely to rise as search and rescue operations progress. Some areas of the state remain inaccessible due to hazardous conditions, flooding, and intermittent cellphone service. Around 14,000 customers remain without power, with the worst hit Breathitt, Knott, Letcher, and Perry counties. Around 360 people have evacuated to 15 shelters and two state parks. Multiple roadways in the region have been made impassable due to floodwaters and residents in some areas were urged to move to higher ground. Authorities declared a local state of emergency in Breathitt, Clay, Floyd, Letcher, Owsley, and Pike counties late July 27, while state officials declared a state of emergency for Kentucky early July 28.

Authorities in West Virginia declared a state of emergency for Fayette, Greenbrier, Logan, McDowell, Mingo, and Wyoming counties July 28, following significant local flooding, downed trees, power outages, disruption to potable water systems, and road blockages. Virginia declared a state of emergency July 28 due to flooding in the southwest portions of the state. Authorities evacuated residents in the town of Pound in Wise County, Virginia due to flooding. Reports indicate significant flooding in Wise Town and Bondtown City in the county.

Government Advisories
As of late July 31, the National Weather Service (NWS) has issued flash flood and flood watches and warnings for parts of eastern Kentucky.

The Weather Prediction Center (WPC) has issued a "Moderate Risk" (Level 3 on a four-tier scale) of excessive rainfall for southeast Kentucky through at least early Aug. 1. There is a "Slight Risk" (Level 2) of excessive rainfall across much of the rest of the affected area through at least early Aug. 2. Officials could update and possibly extend the coverage of weather alerts over the coming days.

Hazardous Conditions
Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days and tornado warnings advising the public to shelter in place. Disruptions to electricity and telecommunications services are possible where severe weather impacts utility networks.

Transport
The severe weather will likely contribute to transport disruptions throughout the region. Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger flight delays and cancellations at airports across the affected region. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation.

Localized business disruptions may occur in flood- or tornado-hit areas; some businesses might not operate at full capacity because of damage to facilities, possible evacuations, and some employees' inability to reach work sites.

Advice

Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments before travel. Make allowances for localized travel delays and potential supply chain disruptions where flooding has been forecast. Do not drive on flooded roads. Review contingency plans and be prepared to move quickly to shelter if tornado warnings are issued. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

National Weather Service