The long-predicted double-dip in housing has begun, with cities across the country falling to their lowest point in many years, data released Tuesday showed.

Prices in 20 major metropolitan areas fell 1 percent in November from October, according to the Standard & Poor’s Case-Shiller Home Price Index. The index is only 3.3 percent above the low it reached in April 2009 and has fallen fell 1.6 percent from a year ago.

“A double-dip could be confirmed before spring,” the chairman of S.&P.’s index committee, David M. Blitzer, said.

Eight of the 20 cities in the index fell to new lows for this cycle, including Atlanta; Charlotte, N.C.; Portland, Ore.; Miami, Seattle; and Tampa, Fla. Only a handful of places — essentially California and Washington — saw prices rise.

Prices in Atlanta and Chicago fell more than 7 percent, exceeding even the drops in the perennially troubled Detroit and Las Vegas.