The website, Weather.gov, is receiving more than five times its usual web traffic.
"We're looking at unprecedented demand from this event," National Weather Service spokesman Curtis Carey told CBS News. "We're talking 15 to 20 million hits an hour on our web servers. That's far beyond anything we've seen in the past."
According to internal reports from the National Weather Service, the surge in traffic and slowdown of servers impacted the weather service's ability to provide storm briefings to key decision makers. In some cases the briefings were uploaded to YouTube instead. Some offices have also had trouble receiving real-time storm reports.
"It is extremely likely that people's safety or lives were jeopardized by this," said Dan Sobien, president of the National Weather Service Employees Organization.
The slowdown began Sunday evening and lasted into the day on Tuesday. Visitors to the website reported having trouble accessing weather forecasts and radar imagery while a large swath of the country was under some sort of weather watch or warning.
The storm has left a trail of snow and ice across much of the United States and has resulted in more than 12,000 canceled flights this week, according to FlightAware.com.
When thunderstorms were approaching northern Alabama Tuesday, Eddie Hicks, director of emergency management in Morgan County, says he was unable to access National Weather Service radar imagery online to track the incoming storms. Hicks, a 31-year veteran of emergency management services, is also president of the USA council of the International Association of Emergency Managers.
"That really makes a difference on the emergency management side because we don't know what a storm is doing if we can't get the [radar] image to make those determinations," he said.
Also affected was an online chat server used by local weather service offices to communicate in real-time with emergency management officials and local media. The chat site was reported to be down much of Monday.
"Frankly the weather service, I believe, has let us down," said Troy Kimmel, a meteorologist at CBS affiliate KEYE. "They've got a major storm on their hands and they can't handle the web traffic."
As of Tuesday evening, the web servers appeared to be running smoothly again.
"The technology that we have in place is just the absolute necessary equipment to keep us operational. It isn't far beyond that, though," said National Weather Service spokesman Curtis Carey.
In 2010 Congress.org ranked Weather.gov one of the top five worst government websites.
Carey said upgrades to the web servers are planned for this spring and summer. But for now, the focus is on keeping Weather.gov online Wednesday while the storm system pounds the eastern part of the country.
"We're not out of the woods yet."