Soldiers have begun airlifting storm-relief supplies to Vermont towns which are still cut off after the trail of destruction left by Irene.
More than 200 roads are blocked or washed away in Vermont, hampering rescue efforts to 13 towns.
Irene killed 44 people in 13 US states, according to the Associated Press, and caused billions of dollars' damage.
President Barack Obama pledged storm-stricken areas would have "the support they need so that folks can recover".
"A lot of our fellow citizens are still reeling from Hurricane Irene and its aftermath," he told a military veterans event in Minneapolis.
'Irene whacked us'
President Obama's remarks came a day after the Federal Emergency Management Agency (Fema) warned of shortfalls in a disaster relief fund.The agency's director, Craig Fugate, toured Vermont by helicopter on Tuesday, after warning that some projects to rebuild areas of the Midwest struck by tornados earlier in the year could be postponed.
Vermont National Guard troops were bringing food, water and other emergency supplies via air and road to the rural and mountainous state.
"We've got a long slog ahead," Governor Peter Shumlin told MSNBC television. "Irene really whacked us hard."
During a trip to storm-stricken North Carolina, Homeland Security Secretary Janet Napolitano said she was unaware of anything federal authorities should have done differently in Vermont.
She added that Fema would continue to work closely with agencies in the state.
Vermont is reeling from its worst floods since 1927, and officials warned some rivers and creeks there had yet to crest.
Irene passed into Canada on Sunday, after causing havoc along the US east coast from North Carolina to Vermont.
Missing men
In eastern Canada, crews continue to clean up debris and work to restore electricity to thousands who lost power. An 81-year-old man who left his cabin in Quebec during the storm was found dead just over a mile away, the CBC reported.
Police are still searching for another man who was swept away in Yamaska, north-east of Montreal, as two cars plunged into a chasm created when a road was washed away in a river.
Most of the 44 storm-related deaths recorded so far in the US were caused by falling trees, ocean waves, downed power lines and raging floods.
Driving rains and flood tides damaged homes and cut power to more than three million people in New Jersey, Connecticut and New York alone.
Meanwhile, nearly 100 people remained stranded in mountain towns in New York State due to washed out roads and bridges. The storm dumped 13in (33cm) of rain on the state.
New York Governor Andrew Cuomo said dozens of bridges and roadways would need repairing and that some of the state's rivers had yet to crest from flooding.
Insurance claims could top $7bn (£4.3bn), the Consumer Federation of America estimated.
Claims for wind damage are expected to be one sixth of the total sum from Hurricane Katrina in 2005, and claims for flood damage one tenth, the CFA estimated.