November 5-7, 2008 Blizzard - Update

Dump 10-plus inches of heavy snow, add several warm, sunny days, and make way for brimming creeks and reservoirs.  Whether problem flooding results from the runoff will depend on the ground's saturation point and the possibility of more precipitation falling this week.

Rapid City Public Works Director Robert Ellis has watched Pactola Reservoir's water level rise rather quickly this month. It now measures 91 percent capacity -- a vast difference since January.

At the beginning of the year, the reservoir was at 45 percent capacity. There have been only a few days since May that the lake hasn't had its volume increase, Ellis said.

"I expect, if we continue in this trend, that we are going to be at 100 percent capacity by this spring," he said.

For every two gallons going into the reservoir, one gallon is being released. The measurable moisture difference deflected some big worries for the city after struggling through years of drought.

As for flooding threats now, "It has risen a lot in one year, but I'm not worried," Ellis said.

The water comes from last week's blizzard, which brought the community to a near-standstill, dumping 10.3 inches of snow on the downtown area and more elsewhere.

Since then, sunshine and moderate temperatures have melted the mounds of snow piled up around Rapid City. For all the accumulation and the aggravation of a $200,000 cleanup effort, the storm actually produced less than an inch of moisture -- 0.84 inch, according to Melissa Smith, a hydrologist and meteorologist at the National Weather Service in Rapid City.

Unlike last spring's storms, which developed into record precipitation in May and a steady onslaught of June rains that led to flooding, Rapid City and surrounding areas were experiencing a dry fall before the blizzard.

"I don't think there will be any flooding, but we could see some ponding of water in areas," she said.

That happens in Box Elder after big storms, but city public works director Allen Steier said he wasn't worried Thursday about rising water levels. Heavy spring rains in June caused some flooding there, but it took that much water for Boxelder Creek to run all summer for the first time in years, and then never more than 18 inches deep, he said.

Anthony Carbajal, Pennington County Emergency Management director, said despite what passers-by see in Rapid Creek, there were no reports of storm-water problems in the Rapid City area.

"I'm sure with the melt-off, we'll have higher runoff than usual, and probably heavier and faster stream flows, but there have not been any reports of flooding at this time," he said.

That doesn't let Rapid City and the surrounding area entirely off the hook, Smith said.

In a quirky parallel, 10 years ago -- on Nov. 6, 1998 -- a blizzard dumped 8 inches of snow at the airport. Last week, Smith said 7.8 inches fell there Nov. 6.

A decade ago, Rapid City received 21.3 inches of snow that November. So draw what conclusions you can from the experience, she said.

"We do tend to get a few of these snowstorms in November," Smith said.

Contact Jomay Steen at 394-8418 or jomay.steen@rapidcityjournal.com.