FARGO, N.D. -- After packing more than a million sandbags and building 20 miles of temporary clay dikes to hold back the surging Red River, swollen from the rapid melting of ice and snow, this city got a lucky break on Friday: a sudden drop to subfreezing temperatures.
While frigid weather might not be considered good fortune on the eve of spring anywhere else, in Fargo, the state's most populous city, the cold snap put the brakes on a sudden thaw and the threat of widespread flooding. Fargo suffered a major flood with similar causes in 1997 and narrowly escaped disaster last year, when the river hit a record flood level of 41 feet.
This time, the river is expected to crest at 38 feet late Saturday or early Sunday, and the city is in waiting mode, having begun preparations months ago. All of the emergency fortifications have been in place since Thursday.
"Things are quiet. Things are looking good," said Karena Carlson, the city's communications director. "Thirty-eight feet is still a major flood, but after last year, I think it would take a lot to put us in panic."
Downtown on Thursday evening, many families seemed more concerned about watching the elephants and lions in a circus parade than worrying about floodwater. But people who live directly on the river were anxious.
"I'm nervous Nellie and would rather have extra protection," said Gloria Hogue, who lives on the river in a subdivision just south of Fargo. "Our driveway is full of sandbags, and the plywood is in the garage, ready to go. It's nerve-racking."
Last year, Fargo built 50 miles of temporary clay dikes. This year the city was able to reduce the amount of emergency construction work because several new flood walls had been built since last spring.
Since the last major floods, the authorities have considered a variety of permanent solutions that would ease the city's transition from winter to spring. They looked at dredging and widening the river, digging tunnels, turning an Interstate highway into an open viaduct during floods, or creating water storage areas.
The idea that emerged with the most support, however, is water diversion. The city is in the midst of devising a $1 billion long-term flood management plan for a large channel that would send some water on a man-made path bypassing Fargo and neighboring communities.
On Thursday, a flood study work group approved $2.4 million for an environmental impact study, and to determine the best diversion route, which is expected to begin 10 miles south of Fargo. (The Red River, which splits North Dakota from Minnesota, actually flows north toward Winnipeg, Manitoba, hence the need for a diversion south of the city.)
The diverted water would rejoin the river around Harwood, N.D., a city official said.
Outside Fargo, many small creeks and streams have already overflowed their banks, turning sugar beet and wheat fields into standing lakes.
Meteorologists said a serious threat of flooding existed across not only in North Dakota -- where spring flooding often happens first -- but also much of the Midwest, the result of an unusually large snowpack that accumulated over the wet winter in the country's upper midsection.
Cities in Minnesota and Iowa are also making flood preparations. Major flooding is expected this weekend and into next week along the Mississippi River in St. Paul, where officials declared a state of emergency and began closing parks and roads near the river. The Mississippi is expected to crest at almost 6 feet above flood stage on Wednesday.
In Stillwater, Minn., city officials were asking for volunteers to help fill 20,000 sandbags on Friday to prevent downtown flooding. They planned to close the city's lift bridge for the first time since major flooding in 2001.
"We're hauling in sand and asking volunteers to help fill sandbags," said Beth Wolf, secretary for the city's engineering and public works department. "We're trying to keep the water back to protect our downtown businesses."
The National Weather Service issued flood warnings for many communities in Iowa, including Des Moines, where there were some road closings.
In Fargo, residents took a wait-and-see approach as they entered the weekend of the river's expected crest.
"Everybody seems to have been better prepared this year," said Pat Slattery, a spokesman for the National Weather Service in the central region office in Kansas City, Mo. "Of course, we started talking last fall about what could happen on the river. People are of the mind-set that preparations have been pretty good."
This article originally appeared in The New York Times .