Percent of Groundwater Recharge Going into Spring will Be Key

Piles of snow don't guarantee recharge.

Published on: Jan 24, 2011

Jim Neman, not a retired climatologist, always said the biggest droughts were made in the fall. This isn't meant to be drought-mongering, but while rains in late November helped, parts of the Corn Belt aren't benefiting in terms of moisture build-up as much form a snowy winter as some might believe. In fact, some areas are running below normal in actual precipitation, even though snowfall is already above average for the same location.

Indiana is a prime example. Snowfall is at or above average in late January, depending upon which part of the state you're targeting, but precipitation totals compared to normal are running an average of 62% of normal. In the southern third of the state, where near drought conditions existed last summer, less than 60% of normal precipitation has fallen form Dec 1 through Jan 21.

The rub is that snow doesn't contain a huge amount of actual moisture. It takes from 10 to 15 inches of snow to reduce to one inch equivalent of rain. Where in the range it falls depends upon the type of snow.

The U.S. remains in the grip of a La Nina event. This means that cooler than normal waters persist in the equatorial Pacific. Many weather experts believe that the type of weather seen across the country and the world so are this winter correlates pretty well with typical winters in the past when La Nina dominated.

What remains to be seen is what happens the rest of the winter. At least one source believes it will be drier yet in later winter. Spring and early summer is still too far to predict.

Weather patterns next summer will obviously be the final ingredient in the mix which will either produce a wet, normal, or dry spring. But Newman believes low fall recharge sets the table for drought because plants can use up reserves very quickly unless you get lots of rain. Once plants start growing, you also have evaporation and transpiration going on.

The bottom line so far is not to be fooled into thinking lots of snow equals lots of moisture and plenty of moisture reserves headed into spring. The rivers may be closer to the truth. Only time will tell.