Boat owners are continuing to help rescue people trapped by rising floodwaters from Hurricane Harvey, now a tropical storm, with forecasters saying rain levels could rise as high as 50 inches in some spots.

FEMA said it expects that 30,000 people will be displaced and that 450,000 will be seeking some sort of disaster assistance, according to the Washington Post; five people were reported dead as of today.

New evacuations were ordered today in the nation’s fourth-largest city as rising floodwaters that turned Houston streets into rivers navigable only by boat now threaten dams across the region — while rescuers pleaded for more boats to reach residents trapped in their homes, according to Fox News.

Over two days Houston got 25 inches of rain — more than half of its annual rainfall — and the amount could more than double in sum this week, according to CNN.

Rainfall from Harvey could reach over 50 inches in spots, the highest ever recorded in Texas, according to the Weather Channel, and catastrophic flooding is expected to continue for days.

Here is a CBS News video of boats rescuing people from flooded roads in Dickinson, Texas:

Harris County Judge Ed Emmett put out a public plea Sunday, asking boat owners to offer any assistance they could, the Dallas News said.

“We desperately need boats and high-water vehicles,” Emmett said at an afternoon briefing on Sunday. “We can’t wait for assets to come from the outside.”

The National Guard and private boat operators searched for residents in distress, many of whom had been calling authorities for help all day long, according to The New York Times.

Stranded residents mounted the backs of some soldiers, who waded through thigh-high waters to take evacuees to trucks that would drive them to safety.

During a break from Sunday’s rain, the unflooded stretch of interstate near a shopping center in southwest Houston became an impromptu staging area for emergency responders and volunteers offering up powerboats, kayaks and rafts, the newspaper reported.

Despite a request from the Coast Guard to call its Houston Command Center for rescue instead of posting on social media, many local residents stranded by Hurricane Harvey are still tweeting pleas for help, according to Tech Crunch.

Some say they keep getting busy signals when they call the Coast Guard. Other Twitter users have also set up accounts specifically for directing rescuers to stranded people.

In a tweet posted Sunday night, the Coast Guard said that if callers get a busy signal, they should keep trying. Several replies pointed out, however, that people who are running out of phone battery can’t keep waiting for someone to pick up.

The Coast Guard said it rescued at least 32 people from several boats on Friday and Saturday.

One rescue, captured on a video released by the Coast Guard, showed one of four people rescued on Saturday being pulled ashore.

They were four of the 15 the Coast Guard said it rescued that day near Port Aransas, Texas.

Seven had been aboard the tugboat Sabine and were airlifted to a rig near Aransas Pass; four were rescued from a vessel called Sandy Point, according to The New York Times.

Here is a Coast Guard video by Air Station Corpus Christi of a rescue near Port Aransas, Texas:

The rescues occurred despite warnings for Texans to stay off the water.

“The Coast Guard search-and-rescue capabilities degrade as storm conditions strengthen,” the Coast Guard said in a statement issued Aug. 25. “This means help could be delayed.”

“If you’ve evacuated, please stay where you’re at,” Capt. Tony Hahn said at a news conference on Saturday afternoon. “The most important thing right now is your safety. Where your boat might be is most likely not a nice place — or not a safe place.”

Read more about Hurricane Harvey as it develops in Tuesday’s issue of Trade Only Today.