A summary on the prospect for flooding in Iowa during the rest of this week.--Bryce

Iowa to get moderate to major flooding this week

* All Iowa rivers may reach flood stage this week

* Rain, snow melt create flooding in Iowa

* Rain to slow grain, livestock movement

CHICAGO, March 9 (Reuters) - Heavy rains combined with snow melt will trigger moderate to major flooding in Iowa ahead of the spring planting season that could hamper transportation of grain and livestock, the state climatologist said Tuesday.

Iowa is a top U.S. top grains producer and the largest U.S. hog producer. Farmers in top grain states such as Iowa and Illinois normally begin planting their corn and soybean crops in April.

"We're not showing a lot of flooding right now, but with continued snow melt and rain forecast, practically every river in the state will get to flood stage within a week," said Harry Hillaker, the state climatologist.

Iowa has had one of its snowiest winters on record, with an average accumulation of 45.7 inches (116.08 cm) for the entire state, and there is possibly more snow to come. Normally, Iowa gets an average snowfall of 32.4 inches (82.3 cm).

The unusually large amount of snow combined with extremely cold temperatures kept a very large snow pack on the ground, Hillaker said.

Now, warmer weather in the last few days created slush and mud, raising concerns about field conditions as a large amount of rain is also forecast.

This week rainfall is expected to average 1.5 inches (3.8 cm) for the entire state. In a typical March, Iowa averages 2.25 inches (5.71 cm) for the entire month.

"This amount of rain is not what you want to see at the same time the snow melt is occurring," Hillaker said.

While muddy feedlots are a given in the spring, the continued wet weather will not give the areas many opportunities to dry out, creating miserable conditions for both the producers and their livestock.

"It's going to be very trying to do everyday chores and the livestock don't like it either, they won't eat very much or gain very much weight," Hillaker said.

And then there's getting the livestock to market. Movement of grains and livestock will be slowed by poor conditions on secondary gravel roads, Hillaker said.

The National Weather issued several flood warnings and advisories for portions of central Iowa through the week.