Storm Cristobal has weakened to a tropical depression after crashing ashore as a lopsided tropical storm a day earlier in Louisiana and sparked dangerous weather farther east, sending waves crashing over Mississippi beaches, swamping parts of an Alabama island town and spawning a tornado in Florida.

Cristobal made landfall on Saturday afternoon between the mouth of the Mississippi River and the since-evacuated barrier island resort community of Grand Isle, with 50mph winds.

Making landfall well under hurricane strength, the storm had begun weakening as it moved inland — but heavy rainfall and a storm surge continued along the Gulf Coast, posing a threat across a wide area into the Florida Panhandle.

With its drenching rain, Cristobal is expected to keep inundating the northern Gulf Coast well into Monday, but all tropical storm warnings have been discontinued.

Cristobal’s forecast path takes it inland through north-eastern Louisiana and south-western Mississippi on Monday, continuing through Arkansas and eastern Missouri on Monday night and Tuesday, and reaching Wisconsin and the western Great Lakes by Wednesday.

The National Hurricane Centre in Miami said additional weakening is expected through Tuesday but some strengthening is expected on Tuesday night and Wednesday.

In New Orleans, the question was how much rain would fall and whether there would be enough breaks in the bands of heavy weather for a beleaguered pumping system to meet its latest test.

Coastal Mississippi news outlets reported stalled cars and trucks as flood waters inundated beaches and crashed over highways.

In Alabama, the bridge linking the mainland to Dauphin Island was closed for much of Sunday. Police and state transport department vehicles led convoys of motorists to and from the island when breaks in the weather permitted.

Forecasters said up to 12in of rain could fall in some areas, with storm surges up to 5ft. The weather service warned that the rain will contribute to rivers flooding on the central Gulf Coast and up into the Mississippi Valley.

It’s very efficient, very tropical rainfall,” National Hurricane Centre director Ken Graham said in a Facebook video. “It rains a whole bunch, real quick.

In Florida, a tornado — the second in two days in the state as the storm approached — uprooted trees and downed power lines on Sunday afternoon south of Lake City, the weather service and authorities said. There were no reports of injuries.

This site uses Akismet to reduce spam. Learn how your comment data is processed.