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Flash Flood — Lehigh, PA

Aug 4, 2020

Tropical Storm Isaias brought high winds, heavy rain, several tornadoes, and coastal flooding to the mid-Atlantic region, becoming the most impactful tropical cyclone to impact most of the region since Sandy in 2012. Flash flooding as a result of heavy rain caused two direct deaths from this event...one in Lehigh County and the other in Montgomery County.

Source: NOAA National Weather Service Storm Events Database (event 928258). Narrative written by NWS staff at the time of the event.

Flood Risk Context for Lehigh, PA

This event is one of many recorded floods in Lehigh County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.

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More Flood Stories

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Post Tropical Cyclone Ida brought heavy rain to eastern Pennsylvania on September 1. Rainfall totals were as high as 5 to 10 inches. The heavy rain caused significant flash flooding, mainly in the southeastern part of the state. It resulted in widespread property damage.

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Flood$1.0M damage

Lehigh, PA · Jan 19, 1996

The combination of snowmelt from the previous week's two storms, unseasonably warm temperatures and an additional one to two inches of rain caused the flash flooding of almost every small stream and significant roadway flooding the afternoon and early evening hours on the 19th.

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Flash Flood$5.0M damage

Lehigh, PA · Sep 18, 2004

The remnants of Hurricane Ivan interacting with a slowly moving cold front caused widespread very heavy rain to fall during the first half of the day on the 18th in Lehigh County.

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Flash Flood$50K damage

Lehigh, PA · Jul 14, 2014

Thunderstorms with very heavy downpours produced flash flooding in the Lehigh Valley and far southeast Pennsylvania during the afternoon and evening of the 14th.

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