As Hurricane Harvey hammers southeast Texas, leaving widespread floods like we've never seen before, some Gulf Coast communities have to make the difficult call to announce voluntary or even mandatory evacuations.

The information they use to make those delicate decisions comes from an office 260 miles away, in Fort Worth, Texas.

"Frankly, these are million-dollar decisions they're making, along with saving lives and saving property," says Gregory Waller.

Waller is the service coordination hydrologist at the West Gulf River Forecast Center, part of the National Weather Service. This office is the only one of its kind in Texas, and one of just 13 nationwide. It's responsible for predicting how rivers will be impacted by rain. It's information that's been crucial, as communities look to protect their own during the ravaging rains.

"We make sure we provide the most accurate information possible, so they can make the best decision possible," Waller says.

Waller says the information in this office also shows when the flooded areas could see some relief, based on current rain predictions.

"It could dry out in the next few days to a week or two with exception of Buffalo Bayou," he says. "The recovery process though, once that starts, we're talking years."

The critical information coming out of this office isn't just for meteorologists and municipalities to use. Anybody at home can access it as well. Their public web site allows you to click on individual areas and see when rivers are slated to crest, and what the dangers are where you live.

"You can't compare it to any other storm," Waller says of Hurricane Harvey's floods.

So they'll continue providing support, hoping it helps keep people safe.