Following the surprise spring cold snap that left much of the country with their flowers buried under snow and torrential rain, it should be no surprise that people are swarming to the warmer climates of the south and west, as the U.S. Census notes accelerated growth in 50 top metros are largely concentrated in those regions.

This year, the Census experienced a watershed moment when the U.S. population turned over to 300 million people. In 1915, there were 100 million. In 1965, there were 200,000 million.

With the population growing at a faster rate than ever, there's a consequential rise in the number of households, expected to grow between 2006 and 2015 by 1.5 million homes annually. That's more than any other period besides the 1970s, when baby boomers became heads of households in record numbers, including a peak divorce rate in 1979.

Immigration plays a large role in the growing population. According to information supplied to agents from the Austin Board of Realtors:

• In the not-too-distant future, over 50 percent of your customers will no longer be Anglo-American

• Each year, 2.7 million people -- the majority of which are non-Anglo -- join the U.S. population.

• Over 35 percent of the youth market (16 to 24 yr. olds) are non-Anglos. These are the homebuyers of the future.

Information on Realtor.org in 2005 stated, "Minorities will grow evermore important to housing markets over the next 10 years, accounting for an estimated two-thirds of new households. They will account for more than 50 percent of first-time homebuyers by 2010, when nearly three in 10 households will be headed by a minority."

The patterns of immigration have changed since the last century, when a majority of Irish and European immigrants came to the U.S. through northeastern ports, causing exponential growth on the east coast. While east coast immigration still occurs, today, most immigration comes from Asia and Mexico (31 percent of immigrants in 2004,) through western and southern points of entries. Approximately 34 million immigrants live in the U.S., with roughly 9 million of those living as illegals.

According to population estimates just released for all metro areas by the U.S. Census Bureau, the Atlanta metro area gained 890,000 residents from April 1, 2000, to July 1, 2006, the largest numerical gain of the nation's 361 metro areas at 5.1 million.

Overall, six metro areas each gained at least 500,000 people between 2000 and 2006.

Dallas-Fort Worth had the second largest numeric increase at 842,000, and totaled about 6 million people. Houston (with an increase of 825,000), Phoenix (787,000) and Riverside-San Bernardino-Ontario, Calif. (771,000) rounded out the top five metro area gainers over the time period. The five metro areas experiencing the greatest numeric change between 2000 and 2006 were in the South or West.

The Northeast metro area with the greatest numeric change between 2000 and 2006 was New York (seventh overall nationally), while the Midwest metro area with the greatest numeric change over the same period was Chicago (10th overall nationally).

New York was the most populous metro area on July 1, 2006, with 18.8 million people, followed by Los Angeles (13 million) and Chicago (9.5 million). Fourteen metro areas had populations of 4 million or more.

Population losses were due to natural disasters and job eliminations. Not surprisingly, the New Orleans metro area experienced the greatest numeric loss from April 1, 2000, to July 1, 2006, declining 292,000 since 2000 to 1 million on July 1, 2006. It was followed by Pittsburgh (a loss of 60,000) and Cleveland (a loss of 34,000). The New Orleans-Metairie-Kenner, La., metro area also had the biggest percentage loss during the same time period at 22.2 percent. It was followed by Gulfport-Biloxi, Miss. (a loss of 7.4 percent) and Weirton- Steubenville, W.Va.-Ohio (a loss of 5.2 percent).

St. George, in the southwestern part of Utah, was the fastest-growing metro area between 2000 and 2006, with a growth of 39.8 percent to total 126,000 on July 1, 2006. Rounding out the top five were Greeley, Colo. (31 percent); Cape Coral-Fort Myers, Fla. (29.6 percent); Bend, Ore. (29.3 percent); and Las Vegas (29.2 percent).

The 50 fastest-growing metro areas were almost evenly distributed between just two regions -- 23 in the West and 25 in the South. One metro area, Fayetteville-Springdale-Rogers, Ark.-Mo., straddled both the South and Midwest regions.

Sioux Falls, S.D., was the lone metro area among the top 50 fastest-growing located completely in the Midwest.

Of the 50 fastest-growing metro areas, none were in the Northeast. York-Hanover, Pa., the fastest-growing metro area in the Northeast, ranked 95th.

The 10 U.S. Metro Areas With Highest Numerical Growth: April 1, 2000-July 1, 2006

10 Fastest-Growing U.S. Metro Areas: April 1, 2000-July 1, 2006

More than four-fifths of all U.S. metro areas (305 out of 361) had a larger population on July 1, 2006, than on April 1, 2000. The 50 fastest-growing metro areas between April 1, 2000, and July 1, 2006, all grew by at least 13.8 percent, which is more than double the nation's total population gain of 6.4 percent during the same time period, suggesting accelerated migration to cities.

As of July 1, 2006, the 361 metro areas in the United States contained 249.2 million people -- 83.2 percent of the nation's population.