Thousands of people may people may be trapped in their homes because they didn’t heed the state’s evacuation warnings before Monday’s storm surge hit “and our worst fears were being reached,“ Gov. Dannel P. Malloy said in a hastily called press conference Monday night around 9:15.

Malloy had urged municipal officials from Saybrook and west of New Haven to evacuate residents as if the storm was a Category 4 storm.

“It is evident that some folks did not urge their residents to evacuate to level four, which, as I told you and began telling people days ago, was the level we thought might be had,” Malloy said. “It became equally clear that even as we gave those warnings some of our residents did not heed them.”

Malloy strongly urged residents in homes experiencing flooding to stay away from windows and get to the highest place in their home, even if that means the roof.

“If you are in a house that is inundated, get to the highest place you have to, given the circumstances you are facing,” Malloy said.

He urged residents in that situation not to try to evacuate now, not to wade through water, or try to drive through water.

“We’ll worry later about who should have done what,” Malloy said. “What I’m most concerned about right now is the loss of human life and what we can do to prevent it.”

He said your only option if your house is surrounded by water is to remain in the house and move to a highest level in the house.

“This is a rather Katrina-like warning that we are issuing to people who did not take the advice that was given to them earlier in this crisis,” Malloy said.

Malloy made the announcement at 9:15 p.m. when there were two more hours of “tide gathering” in the Long Island Sound. High tide was expected around 11 p.m.

In the lower portion of Long Island Sound from New Haven to the west, there are four to five foot seas, which could surge from seven to 11 feet.

As power outages began to climb to more than 270,000 around 6 p.m. Monday evening, Hurricane Sandy was just making landfall in New Jersey. By 8:30 p.m. the number of outages between the two largest utilities neared 550,000 and the number was expected to increase as the state braced for another storm surge.

The southeastern part of the state was hard hit by the first part of the storm, but power outages from winds as high as 80 mph and felled trees began to take their toll on other parts of the state as well.

Malloy warned that the two utilities can’t start restoring power until the winds drops below 40 mph.

“If you lose your power. You’re likely to be without power for an extended period of time,” Malloy said.

There were 40 road closings as of 6 p.m. Half were caused by flooding and half from downed trees. Malloy urged everyone to stay off the roads until the storm passes Tuesday. He said the truck ban is still in effect and “unless your life depends on your leaving your home, then don’t.”

All non-essential state employees have been asked to stay home again Tuesday.

“I’ve made clear to utility companies what they already know: Everyone is watching to see how they perform,” Malloy said.

United Illuminating Senior Vice President Anthony Marone III said to protect its New Congress and Pequonnock substations from flooding in Bridgeport, UI needed to take them offline before the evening storm surge. The decision to de-energize those substations impacted 52,000 customers — 47,000 of which are in Bridgeport.

The utility is monitoring the Mill River substation in New Haven, but at the moment there are no plans to de-energize it, Marone said.

“If the substations flood while they’re energized, the results could be catastrophic and could take weeks to repair,” Malloy said.

Connecticut Light & Power also is taking steps to protect their substations in Stamford and Branford, but they did not anticipate having to de-energize either of them on Monday night.

William Quinlan, senior vice president of emergency operations for CL&P, said tidal waters were still about a mile from the Stamford substation. He said they will try to bring in back-up generation if they need to take down the Branford substation, which serves about 11,000 customers.