An aerial view shows a building housing that had its roof blown off during a tornado spawned by Tropical Storm Cristobal. The EF1 tornado passed through Orlando, Florida, leaving at least 8 homes damaged, along with numerous reports of downed trees and power lines. No injuries have been reported. (Paul Hennessy / SOPA Images/Sipa USA via AP Images)

Cristobal, now a tropical depression, is heading inland Monday after bringing flooding to the Gulf Coast over the weekend.

The storm made landfall Sunday around 5 p.m. CDT along Louisiana's southeastern coast between the mouth of the Mississippi River and Grand Isle.

As of 10 a.m. CDT Monday morning, . The National Weather Service issued flash flood watches from the northern Gulf Coast and the lower Mississippi Valley northward through Missouri to parts of the upper Mississippi Valley.

(MORE: Tropical Depression Cristobal's Inland Track to Bring Flooding Rain and Strong Winds)

Heavy rains and storm surge continued Monday morning, with winds from the south pushing water out of the northern side of Lake Pontchartrain. Slidell, Louisiana, saw flooding in some neighborhoods, . In Mandeville, floodwaters extended at least three blocks from the lakefront, covering many of the community's streets.

The Coast Guard is still searching for after launching from Salt Bayou near Slidell about 1 p.m. CDT Sunday, NOLA.com reported.

Cristobal brought flooding to the Gulf Coast Sunday, and water levels were measured at about 6.2 feet above normal tide level at Shell Beach, Louisiana. New Orleans saw storm surge surpassing 3.5 feet on the south shore of Lake Pontchartrain Sunday afternoon, causing water to flood Lakeshore Drive.

Much of Grand Isle in Jefferson Parish, Louisiana, was underwater, and inundated roads prevented authorities from reaching.

Storm surge also flooded roads near Waveland and Bay St. Louis, Mississippi, where water levels were nearly 6 feet above normal Sunday afternoon.

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Rainfall reached rates of 3 to 6 inches per hour Sunday morning, triggering significant flash flooding in parts of downtown Jacksonville, Florida, where there were reports of trapped cars.

An EF1 tornado spawned by the tropical storm touched down in Orlando, Florida, on Saturday evening, damaging at least eight buildings and displacing as many as 50 people.

In southeastern Marion County, Florida, a sinkhole opened up along State Road 35 and Dogwood Road, shutting down the highway in both directions early Sunday. The sinkhole occurred due to heavy rain saturation, and knocked down a concrete utility pole and a road sign.

Cristobal's area of low pressure is forecast to move from the lower Mississippi Valley on Monday to the Midwest by Tuesday, bringing flooding rain, strong winds and possible isolated tornadoes.