Even when floods can be anticipated, communicating their severity to the public is a tall order. Because flash floods are very localized, even neighborhood-level warnings may seem like false alarms to some residents, leading to what the journalist Zoë Schlanger has dubbed “ alert fatigue .”

Meteorologists issued urgent warnings for parts of Southern California amid heavy rainfall that flooded the region.

Denver7 is tracking the latest Colorado weather alerts as strong-to-severe thunderstorms are firing up Wednesday night.

An amber warning covers a large swathe of southeast England, including Greater London, from 4am until 11am on Saturday, with concerns about flash flooding, travel disruption and possibly power cuts. Yellow warnings for heavy rain and thunderstorms cover much of Scotland and England on Saturday, as the wet weather spreads northwards.

Due to the prolonged period of dry weather some areas are at risk of flash flooding as heavy rain hits parts of the country

A flash flood warning was in effect in New York City until 9:45 p.m., and New Jersey Gov. Phil Murphy declared a state of emergency. Middlesex, Morris and Somerset counties remained under a flood warning until 7:15 a.m. Tuesday.

Dangerous flash floods stranded motorists and left roadways under water. Some outdoor activities were canceled as communities scurried to keep pace with the rising waters.

Through the rest of the evening on Sunday, the NWS is predicting a level two of four (slight) risk of storms across the majority of South Central Texas. Rainfall amounts of two to four inches is expected, while some areas could see pockets of nine to 12 inches of rainfall in certain regions.

A severe thunderstorm warning has expired but a flash flood warning remains in effect for parts of Allegheny, Washington and Westmoreland counties. The warning is in effect until 8:45 p.m. Wednesday.