Flash Flood — Ottawa, Ohio

2023-08-23 to 2023-08-24 · near Catawba Is, Ottawa, Ohio

Event narrative

Widespread roadway and basement flooding across Catawba Island. One water rescue was reported at a campground in Catawba Island. Radar estimated 5.5 to 6 inches of rainfall in a four hour period ending around 400 AM EDT on August 24, 2023, with a bulk of the rain falling in roughly 2.5 hours.

Wider weather episode

An anomalously-warm and moist air mass was in place across much of the Central Plains and Midwest, resulting in strong to perhaps extreme instability in addition to tropical-like precipitable water values exceeding 2.0 inches. The Lower Great Lakes region, specifically northern Ohio and Northwest Pennsylvania found itself on the eastern edge of this heat dome. Strong northwest flow aloft persisted along the periphery of the anomalously-warm and moist air mass, allowing for organized storms to develop across northern Ohio and Northwest Pennsylvania. A constant feed of moisture allowed these storms to maintain their intensity throughout the evening and overnight hours of Aug 23, 2023 and into the early morning hours of Aug 24, 2023 as they slowly pivoted southwest. Numerous flash flood warnings were issued with 3 considerable tags utilized throughout the course of the event. The hardest-hit areas were along the lakeshore between Toledo and Cleveland where there were several reports of 5 to 7 inches of rainfall. Elsewhere, generally 2 to 4 inches of rainfall was common, most of which fell in only a few hours. The area was on the edge of an extremely unstable airmass with sufficient deep-layer shear for organized convection.

View location on OpenStreetMap → (41.5739, -82.8563)

Source: NOAA Storm Events Database, event_id 1144367. Narrative written by the NWS forecast office that issued the report.