The wildfires that have consumed 1.6 million acres of Texas plains and pines, threatened its capital, and destroyed 240 homes is stretching, but not yet stressing, the United States' wildland firefighting capability, the US Forest Service says.

On Sunday, Gov. Rick Perry acknowledged that Texas needs more federal help to deal with the situation, as dozens of fires are now burning largely uncontrolled across the state, including unusual "crown fires" in tops of trees in the east Texas pine barrens that are leaping to 100-foot heights.

"The request for assistance truly is of historic proportions," says Randall Barr, the fire chief of Tomball, Texas, near Houston. "Everybody is stretched, and the conference calls we're on every day paint a bleak picture, with no relief in sight."

Nearly 8,000 fires – ranging from small to vast – have been reported in Texas since the start of the year, as unprecedented dry conditions, large amounts of winter-cured brush and grass as fuel, and howling winds have kept nearly the entire state at risk for "explosive wildfire potential," the Texas Forest Service reports. In the past week alone, wildfires have spread across an area the size of Rhode Island.

"Fronts are coming through the state on a regular pattern, bringing with them strong winds and low humidity," Governor Perry wrote to the White House on Sunday. "Wildland fires occurring under these conditions are generating intensities that are creating very high difficulties of control ... [and] resulting in extreme fire behavior and conditions that threaten any and everything in a fire's path."

State capital threatened

The state reported 20 new fires on Sunday alone, including one near Austin started by a homeless man who went on a beer run, leaving his campfire unattended. Ten homes have been heavily damaged in the fire, which is now 50 percent contained near the Austin city limits.

"Texas certainly planned on fighting some wildfires this year, but we never planned on this type of situation," says Marq Webb, a spokesman for the Texas Forest Service, in Merkel. "This is off the charts, unprecedented, we've never seen it this bad. It's a historical time in Texas wildfire history."

The US Forest Service currently has hundreds of firefighters from dozens of states working in mobile strike units on fires. The Texas Forest Service reports that about 1,400 state and US firefighters – not including volunteer and local firefighters – are in the field now. So far, the fires haven't come close to using up the US Forest Service's reserves, which include 10,500 firefighters and more than 1,000 pieces of available firetrucks and firebreak-cutting bulldozers.

"Competition for for firefighting assets is low nationally, which means our availability is good," says Becky Rine, a program specialist at the US Forest Service in Washington.

Incidents like the Texas fires "keep us sharp," says Ms. Rine, "so to say that it stretches us, well, it doesn't stress us. We have adequate resources."

Fire can advance 100 yards in a minute

Among the developments:

The federal government is beefing up its presence in Texas, this weekend deploying four 3,000 gallon tanks that can be strapped to C-130 refueling aircraft to turn them into a modified air tanker. Washington also sent a modified DC-10 that can hold 11,000 gallons of fire retardant.

National Guard Blackhawk helicopters are on the scene at the PK West fire in Stephens County, which has already burned 50,000 acres. Nearly 500 homes are currently being threatened near Possum Kingdom Lake, and the town of Strawn has been evacuated.

Ten 20-person crews are tackling the stubborn Rock House fire in Presidio and Jeff Davis counties. Eight pump trucks, several air tankers, and helicopters are buzzing the fire.

Dozens of crews managed to contain 50 percent of the Jackson Ranch fire in Stephens County, but the fire made a major run toward Caddo, Texas, on Sunday, causing the entire community to evacuate.

Despite assurances from the US Forest Service that resources are not a problem, the fact that dozens of fires are starting every day and nearly the entire state is now colored red on fire warning maps is testing the Texas Forest Service's logistical ability to deploy assets.

"It's a pretty complex machine that's running this and it's gotten more complex by the day," says Mr. Webb at the Texas Forest Service.

Without breaks in the dry weather or significant wind changes, fire crews are being forced to work the back end of fires as the front edges tick along so fast at times that they cover the length of a football field in 60 seconds.

"You just do what you can safely and keep working the flanks of these fires until it's at such a point that you can get air resources in or get a break in the wind so we can actually go ahead and pinch the head of that fire off," says Webb.

While the situation is far from under control, firefighters and residents have made major headway in thwarting more destruction. In his letter to Obama, Perry said 8,514 threatened homes have been saved from the flames.