Responding to the worst flu outbreak in several years, one local hospital has opened a mobile emergency room tent to handle the overflow of flu cases.

The tent at Lehigh Valley Hospital's Cedar Crest campus in Salisbury Twp., Lehigh Co., opened Tuesday morning.

"Right now, we are the midst of an extremely busy flu season," said Terry Burger, the hospital's director of infection control and prevention.

This flu season is so busy that Lehigh Valley Hospital has opened an auxilliary emergency room just to handle the overflow. Over the weekend, some patients reported up to seven-hour waits.

"We've had two really mild seasons, so now we're being brutally reminded how bad influenza can be," said Burger.

This year's flu strain, called H3N2, is particularly virulent, Burger said.

"Even people that have gotten the flu shot can also get ill," she said.

So when is your flu severe enough to head to the hospital?

"Having trouble breathing is a clear sign you need to seek medical attention," said Burger. "If you've got underlying heart disease, and you feel like your symptoms are getting worse, you need to seek medical attention."

The tent will open be open until 11 p.m. Tuesday. After that, the hospital will decide day-to-day whether to keep it open.