July 10 (Bloomberg) -- California Governor Arnold Schwarzenegger said his state is approaching a ``tipping point'' in its battle against more than 300 wildfires and needs federal help to turn the tide.

The state requires assistance, including from the military, after lightning sparked the blazes, which have been exacerbated by high temperatures and dry grass and brush, Schwarzenegger wrote in a letter sent to Republican President George W. Bush today.

``With more lightning storms forecast for later this week, we sit at a critical tipping point in California that requires immediate federal help and aggressive pre-positioning of federal resources,'' wrote Schwarzenegger, also a Republican. ``I respectfully request federal active duty forces.''

More than 1,090 square miles, an area roughly the size of Rhode Island, has burned in California since June 21, according to the California Department of Forestry and Fire Protection, also known as Cal Fire. Excessive heat warnings and red flag warnings, which mean conditions are right for ``explosive fire growth,'' cover a 659-mile (1,060-kilometer) stretch from the Oregon border south to Los Angeles.

White House spokesman Scott Stanzel said federal officials are working with California to help battle the blazes and are reviewing Schwarzenegger's request.

Help From Abroad

California will get as many as 40 fire managers from Australia and New Zealand to help coordinate the battle against the fires. The group will arrive in the U.S. this weekend and will be dispatched to California after a training period in Boise, Idaho, said Don Smurthwaite, a spokesman for the National Interagency Fire Center in Boise. It will be the fifth time the two countries have sent the U.S. help.

``They are coming at a good time,'' Smurthwaite said. ``They will provide some relief to an area where we need them.''

Excessive temperatures and low humidity are spreading across the west, with parts of Oregon, Washington, Idaho and Montana also covered by red flag warnings.

Redding, California, 146 miles north of Sacramento, set a record high of 113 degrees Fahrenheit yesterday (45 degrees Celsius), breaking a 2002 mark of 110 for the day.

The heat will start breaking tomorrow, the National Weather Service forecasts. The temperature in Sacramento will fall from 105 today to 95 this weekend.

Resources Stretched

With fires currently burning in 11 U.S. states, federal officials are concerned resources may be stretched too thin, Smurthwaite said.

Smurthwaite said last week the government was considering sending about 500 U.S. Army troops to California. The idea was shelved when the state called up about 400 members of its National Guard.

Schwarzenegger is also asking the government to give the U.S. Forest Service permission to act to save lives and property without having to worry about budget restrictions.

Seventy-seven firefighters have been injured since June 21 and one died, while 190 buildings, including 99 homes, have been destroyed and another 16,417 are threatened.

``We did have a spike in heat injuries yesterday,'' said Janet Upton, a spokeswoman for Cal Fire. ``We are trying to get through until tomorrow morning. We can certainly use some help from Mother Nature.''

Aside from the heat, smoke drifting from the fires has forced the National Weather Service to warn people to keep themselves and pets inside.

Hazy Days

In Truckee, California, about 40 miles northeast of fires burning in the Tahoe National Forest, the smoke has been an intermittent problem, said resident Jenny Franklin.

``Yesterday was the worse I have seen it,'' Franklin said by telephone. ``It looked really hazy and the sun was really orange. Today it hasn't been too bad.''

She said her parents vacationing at Lake Almanor, about 80 miles to the north, haven't been able to go outside because of smoke from fires in Paradise, California, where thousands were evacuated.

Currently, 19,704 firefighters from 41 states are battling 322 fires that have forced thousands of residents across the state to leave their homes. Some have been forced to evacuate more than once.

Rainfall in northern California has been 30 to 40 percent below average and the snow pack in the mountains, which provides water in the form of runoff, was 35 percent less than it should be, according to Jeff Kopps, a National Weather Service meteorologist in San Francisco. In southern California, the past rainy season, which ended in June, was among the ``driest on record,'' he said.

On June 4, Schwarzenegger declared a drought because of two years of low rainfall and dwindling snowmelt.

To contact the reporter on this story: Brian K. Sullivan in Boston at bsullivan10@bloomberg.net.

Last Updated: July 10, 2008 17:19 EDT