Heavy rainfall is forcing Avista to open the main spill gates of the Post Falls Dam in order to prevent Lake Coeur d?Alene from rising too far, and that sent skippers along the Spokane River scrambling to move their boats to deeper water.

Avista opened the main gates of the dam Monday afternoon, which is causing the water behind the wall to drop dramatically. Boat owners were advised by Avista to move their boats to a location where they won?t be grounded.

?It's more rain in June than I've ever seen is this part of the county,? Jim Brush with the Spokane River Association said.

The elevation of the lake at the Spokane Street Bridge east of the Post Falls Dam is about three feet below summer lake levels; once the big spill gate opens the river will drop as much as seven feet below summer level.

The power company is opening the gates at the dam to allow for the increased flow in the Spokane River caused by heavy rainfall in the mountains of North Idaho over the last 24 hours, which has caused Lake Coeur d?Alene to rise.

?It?s been a record or close to it for the month of June,? boat owner Dave Anderson said.

Lake Coeur d?Alene is currently slightly above its normal summer level of 2,128 feet above sea level which Avista is required to maintain until after Labor Day. With more water flowing into the Spokane River Avista is opening the gates so the lake level stays at 2,128 feet.

This is the third time this season Avista has had to open the gates over the dam, an unprecedented event in recent history. Usually Avista just buttons up the dam after the snow melts, the water levels come up and stays at the same level all summer.

In early June the water levels along the Spokane River fluctuated greatly; people who had their boats in the water had to pull them out before they ended up marooned on the shoreline. Some owners were frustrated with Avista?s advance notice ? or lack thereof ? to warn boat owners.

This time around Avista warned people who live on the river and most boat owners had a chance to respond.

?I also had a couple phone calls from neighbors and people who got the information before I did including Avista, Avista called me directly and warned me it was going to go down but they were going to try to give everybody time to get the boats out and I just had time," Jim Brush said.

The heavy rainfall during June is to blame for the changing lake levels and Avista being forced to open the spill gates on the Post Falls Dam. For example upstream in St. Maries they?ve received 5.7 inches of rain so far this month; they usually get only two inches of rain in June.