Skyrocketing housing prices are driving people from San Francisco, Boston and other big cities. Warm weather and more affordable living are behind the rapid growth in midsize cities in Florida, Arizona, Nevada and California.

Census Bureau (search) figures being released Thursday show no letup in the migration to the South and West, which are home to all 10 of the fastest-growing cities with at least 100,000 people.

The Phoenix suburb of Gilbert, Ariz., topped the list. The city grew by more than 46,000 people, or 42 percent, to just over 156,000 residents in a little over four years.

Next on the list ranked by percentage gain was Miramar, Fla., followed by North Las Vegas, Nev.; Port St. Lucie, Fla.; and Roseville, Calif. Rounding out the top 10 were Henderson, Nev.; Chandler, Ariz.; Cape Coral, Fla.; and Rancho Cucamonga and Irvine, both in California.

San Francisco and Boston found themselves among the cities losing the most people between April 2000 and July 2004. Boston, for example, shed more than 19,000 people, or 3.4 percent of its population. San Francisco lost 32,000, or 4.2 percent.

"People like to live in smaller places and a lot of it's propelled by the sharp spike in housing costs in the inner and more attractive cities," said William H. Frey, a demographer at the Brookings Institution in Washington. "People want to get as much housing as they can for their dollars."

The median price for a single-family home in Gilbert is around $220,000, compared with more than $387,000 in Boston and $641,000 in San Francisco.

Peter Ragone, a spokesman for San Francisco Mayor Gavin Newsom (search), said the city recognizes the problem and has begun a number of affordable housing initiatives, such as redevelopment projects aimed at producing more moderately priced homes.

Greg Svelund, city spokesman in Gilbert, said many new residents are coming from higher-priced communities in California. Gilbert adds an estimated 1,000 residents a month, he said.

Miramar, the second-fastest growing city, has undergone a revitalization project in the past decade, Mayor Lori Moseley said. The newest addition to the city south of Fort Lauderdale is the 54-acre Town Center, which houses government offices. Plans call for a cultural arts center that will include an 800-seat auditorium, as well as retail stores and restaurants.

"We want to be a city that you can live, work, play and prosper in," Moseley said.

Another Florida city, Port St. Lucie (search), experienced the largest population growth for a one-year period beginning in July 2003. It added nearly 13,000 people — a 12 percent jump.

Older, industrial cities in the Northeast and Midwest continued to lose residents. Among them were Detroit, Pittsburgh, Cincinnati and Cleveland.

"In those places, they've been on a steady slide since the 1950s. And most of them have not had a single up-decade since the 1940s," said Robert Lang, demographer and director of the Metropolitan Institute at Virginia Tech in Alexandria, Va.

Lang said there is not one particular reason, such as the departure of manufacturing jobs, to explain the losses. But none of the cities attracts new residents through immigration, he said.

In San Francisco and Boston, which had populations booms in the 1990s, Lang said the high-tech bust was a major factor in the declines since 2000.

"This is not shaping up to be a good decade for older cities in the United States in contrast to the 90s," said Lang. "This performance probably doesn't rival the 70s, which stand out as the worst decade, but looks to be underperforming even the 80s."