ND climatologist: 2019 flood not shaping up to rival 2009 record
FARGO — The coincidence of gearing up for a potential major flood fight as Fargo-Moorhead is about to observe the 10th anniversary of its record flood invites inevitable comparisons:
Will the 2019 flood-in-the-making be in the same category as the record flood, which crested on March 28, 2009, with a Red River level of 40.84 feet?
Unlikely, according to North Dakota’s state climatologist.
The conditions that created the 2009 flood were highly unusual, and so far the conditions that are lining up to produce this year’s spring flood are not nearly as severe, said Adnan Akyuz, the state climatologist and professor of climatology at North Dakota State University.
“I have heard from several others that the conditions were comparable to 2009,” he said. “I didn’t think so, but decided to check.”
He did so, he said, “To give them the opposite of a scare, maybe comfort.”
The record 2009 flood had its origins in the fall of 2008, the wettest on record. Similarly, the fall leading up to the 1997 flood, the second-highest on record with a crest of 39.72 feet, also was quite wet, the 15th wettest on record.
By comparison, the fall of 2018 was wet, but merely the 38th wettest on record.
Fall moisture is important, Akyuz said, because it’s something like a savings account. Heavy fall moisture limits the amount of water the soil can absorb during the spring thaw.
“Right now we have some capacity left” in the soil, which will help when the runoff comes, Akyuz said.
The record flood of 2009 and near-record flood of 1997 also were preceded by unusually snowy winters, with the fourth- and third-highest accumulated precipitation on record, respectively, he said.
Although snowy, the winter of 2018-19 was Fargo’s seventh wettest.
Also, the 2009 flood came after heavy rain fell in March, quickly melting the winter snowpack.
As of mid-March, the Fargo area had received 8.38 inches of moisture since Oct. 1. That compares to 14.66 inches for the same period in 2008-09 and 13.45 inches in 1996-97, according to figures from the National Weather Service.
Winter moisture, however, is an imperfect flood indicator. Consider that the wettest four winters were followed by major spring floods in Fargo — but the fifth and sixth wettest winters weren’t, Akyuz said.
The spring thaw so far has been gradual, with melting temperatures during the day and freezing temperatures overnight. And the forecast for next week calls for more of the same.
“Melting is going to trickle, which is a perfect recipe,” Akyuz said.
Those conditions should moderate the spring flood — but officials and property owners shouldn’t get complacent. They still need to prepare for a major flood, he said.
“Still a lot of snow is waiting to melt,” which could coincide with heavy spring rains, Akyuz said.
Although hesitant to make his own forecast about the magnitude of the spring flood, “2008-09 has a low probability of repeating,” he said.
The weather service’s last probabilistic flood forecast, issued in mid-March, gave a 95 percent chance that Fargo will see a crest of 33.8 feet, a 50 percent chance of a peak of 37.9 feet, 25 percent for a 38.9-foot crest and a 5 percent chance of a 41.4-foot flood, which would top the record.
Greg Gust, a weather service meteorologist who closely tracks flood conditions, generally agrees with Akyuz’s comparisons.
“That’s why we’re saying it's not ‘09 and it’s not ‘97, but it’s still a significant flood and a potential Top 10 in terms of runoff,” he said.
Fargo-Moorhead still is likely to see a Top 10 flood year, he said. “A big flood year by any measure,” Gust added, “but not necessarily a ‘record’ flood year — unless some catastrophic conditions come into play, as is the case in the Sioux Falls and Omaha areas.”
Both cities, located in South Dakota and Nebraska, respectively, saw severe flooding triggered by a very rapid thaw coinciding with heavy rains on frozen ground, Gust said.
Fargo-Moorhead must be prepared in case similar conditions develop here, he added.
“We’re not trying to beat a drum that says it’s bad, bad, bad,” Gust said. “Yet it’s bad enough that people still have to do stuff.”