BILLINGS (AP) — Federal lawmakers from states along the Upper Missouri River asked the U.S. Army Corps of Engineers on Wednesday to disclose steps it’s taking to prepare for potential spring floods as snowpack levels continue to climb in the Rockies.

So far this season, snowpack levels at high elevations in the Missouri River basin are comparable to 2011, when flooding devastated hundreds of thousands of acres of mostly farmland in North and South Dakota, Nebraska, Iowa, Kansas and Missouri.

It’s still too soon to say if the stage is set for a repeat this year. April, May and June historically are some of the wettest months in the basin.

But members of Congress from Montana, North Dakota and South Dakota said in a letter to Army Corps Brig. Gen. John Kem that it’s critical for communities along the river to be prepared.

The lawmakers want to know what infrastructure repairs and improvements have been made since 2011, and how the Corps of Engineers is managing a network of major reservoirs along the Missouri River to limit the flood threat.

“Many of our constituents are understandably concerned about what high snowpack levels mean for the potential for flooding,” they wrote.

The Corps’ water management chief for the Missouri River said last week that there are some key differences between 2011 and this year: A 2012 drought left more water storage capacity in the three Missouri River reservoirs in the Dakotas and Montana, providing a buffer against flooding. Also, there is less snow accumulation on the plains than three years ago.

Despite low-elevation flooding in areas of Wyoming and Montana in recent days, the major spring runoff is unlikely to arrive until mid-May, when warmer temperatures melt the deep snows high in the Rocky Mountains.

That means officials will have a better picture of what’s in store for downstream states in coming weeks, after the snowpack peaks likely sometime in April, said Brian Domonkos, a water supply specialist with the Natural Resources Conservation Service in Bozeman.

“2011 was setting up to be a pretty good year, but at this point it wasn’t epic, it wasn’t special. From this point on in 2011 is where we really started to get impressive snow accumulation numbers,” Domonkos said. “That’s going to be the real comparison point.”