US South-west heatwave intensifies, spreads east

LOS ANGELES • A baking heatwave that has gripped the US South-west for three days has spread eastward to Iowa and Missouri, while punishing the hardest-hit areas with record high temperatures that have strained power systems.

The National Weather Service issued excessive heat warnings for much of the South-west, including Arizona, southern Nevada, much of California and southern Utah on Thursday.

Heat advisories were issued for parts of the Central Plains, including Kansas, Nebraska, Iowa and Missouri.

"It's a pretty big impact with respect to where the record heat is," National Weather Service meteorologist Bob Oravec said from the Weather Prediction Centre in College Park, Maryland.

A high-pressure system has been parked for three days over the South-west, a region used to temperatures of around 38 deg C between now and September.

"But now the temperatures in the last several days, especially today, are going anywhere from 10 to 20 degrees Fahrenheit above average," Mr Oravec said.

Salt Lake City in Utah on Tuesday tied its all-time high temperature since record-keeping began in 1894, at 42 deg C.

California's Death Valley National Park, typically one of the hottest spots in the world, recorded 54 deg C on Wednesday.

With air conditioners cranked up in homes and businesses, Texas and California urged consumers to conserve energy during peak times to avoid blackouts.

"The public's help is essential when extreme weather or other factors beyond our control put undue stress on the electric grid," said Mr Elliot Mainzer, chief executive of the California ISO, which operates the grid in most of the West Coast state.

The Electric Reliability Council of Texas, the state's grid operator, expected demand on Thursday to have broken the June record set on Monday.

Both states have previously imposed rotating or controlled outages to prevent more widespread collapses of their power systems - California during a heatwave in August last year and Texas during a brutal freeze this February.

The National Weather Service has also issued red flag warnings across the South-west to warn of fire dangers and major blazes were burning across the region, although most of them were more than 50 per cent contained as at Thursday afternoon.

A cold front is expected to bring relief to the mid-section of the country tomorrow as temperatures in the South-west slowly moderate as well.

"The heatwave, at least the record portions of the heatwave, looks like it will be coming to them this weekend," Mr Oravec said.

REUTERS