The latest round of wet weather is pushing Lake Tahoe's waterline toward its natural rim.
The lake received nearly 26,669 acre-feet of water over the weekend.
Scientists with the National Weather Service in Reno say its unusual for the rise to happen so quickly.
Tim Bardsley is a hydrologist with the service and says most of the water came in the form of rain.
Tahoe's lake level is slightly below the point at which it can naturally flow into the Truckee River, but Bardsley sayd a pair of storm systems moving into the area this week will likely change that.
"Won't take very much at all now to put it up over that natural rim, in which case it can flow out through the dam at Tahoe City, and be controlled at that point."
Bardsley says the stronger of the two storms is expected to hit on Thursday into Friday.