In a 9:15 p.m. press briefing Monday evening, Gov. Dannel Malloy issued a “Katrina-like warning” to steel the state for Hurricane Sandy — a storm which had already caused significant upheaval across the state.

The storm, which officials say could see up to 600,000 Connecticut Land and Power customers face power shortages, made landfall in New Jersey at 6:45 p.m. Downed power lines and widespread flooding were reported throughout the tri-state region, with Malloy urging those who had failed to evacuate to get to the highest levels of their homes and “ride this thing out.”

City Chief Administrative Officer Robert Smuts ’01 said that once the need for evacuation due to high tide has been monitored, attention will turn to recovery and clean-up.

“I think our biggest concern is those areas where we’re worried about flooding. There is the potential to have greater flooding than we’ve had for at least a century in New Haven,” Smuts said. “We have urged evacuation and we are also prepared for the people who have not followed these instructions. Outside these areas, this is a pretty rough storm, but this is nothing extraordinary.”

While city officials ordered residents to evacuate areas of the city prone to flooding Sunday night, some residents remained behind during the peak of the storm on Monday. Flooding affected parts of the city close to the water, and United Illuminating reported nearly 5,000 New Haven residents without power as of 2 a.m. Tuesday morning.

Malloy ordered local officials in shoreline towns to “high alert” after an 8:15 p.m. emergency call with city officials from coastal cities. Describing the situation in coastal regions as “dire,” he called for an immediate evacuation of coastal towns for a Category 4 event, the highest possible warning. Coastal regions in New Haven were listed as being of substantial concern for major flooding.

“I’ve told the mayors and first selectmen that they have no time to waste,” Malloy said. “To the extent they have the ability to order mandatory evacuations I’ve told them must give this their highest priority. I was covncerned all along about the potential destructive impact of this last high tide, and unfortunately the best information we have confirms my worst fears.”

Malloy’s announcement came in response to the National Weather Service’s issue of a high wind warning and coastal flood warning in Connecticut, which said that “historic and life threatening flooding” could occur up until 3 p.m. Tuesday. Tidal surges were expected to be up to 11 feet beginning Monday evening on western Long Island Sound, with breaking waves of 15 to 20 feet on ocean-facing shorelines in southern Fairfield, southern Middlesex, southern New Haven and southern New London. The National Weather Service further reported that Sandy will move faster than expected at about 28 mph, causing wind gusts of up to 90 mph along immediate south-facing coastlines of the same regions Monday evening.

Though Sandy was downgraded to a tropical storm by forecasters after it made landfall in New Jersey with maximum sustained winds of 80 mph, it cut power to nearly a million New Yorkers and threatened Manhattan’s southern tip with a record 13-foot storm surge. One man was reported to have died after a tree fell on a house in Queens, and another reportedly died from electrocution. Reports of flooded subway lines, continued strong wind gusts and power loss in lower Manhattan came in throughout Monday night.

Speaking on behalf of Connecticut’s Emergency Operations Center Monday evening, Rick Fontana said the unprecedented tidal surge expected is causing concern with regards to areas that are close to the coastline.

“I would certainly not say that everything is under control,” Fontana said. “We are still in the middle of the response to a Category 1 hurricane. The Emergency Operations Center is coordinating together and trying to do the best job we can to protect public safety in the city of New Haven.”

Adding to Mayor DeStefano’s Monday morning closure of the City Hall and reiteration of the need for shoreline residents to evacuate, Gov. Malloy announced road closures for all state highways at 1 p.m. He also signed four executive orders to assist Hurricane Sandy recovery efforts, which he said will allow tax-filing extensions to Connecticut residents and businesses along with faster restoration of state power infrastructure.

Some Connecticut communities, including Chester and Killingworth, reported as much as 100 percent of residents without electricity, while downed power lines created hazardous areas in the city of Tolland, Conn. Throughout the day, residents seeking refuge from the storm due to flooding and power outages arrived at storm shelters. In West Haven, more than 100 people were housed in the emergency center at Carrigan School Monday afternoon, while Jonathan Law High School in Milford saw up to 35 residents arrive. Staffed by city personnel and volunteers, the shelter is providing three hot meals a day to residents and also accommodates animals.

Malloy directed all non-essential state employees not to report to work on Tuesday.