Violent storms in Northern California have deposited 33.6 billion gallons of water into Lake Tahoe, where the water level has risen by an entire foot since January 1.

The appearance of a 12-inch-high sheet of water would be dramatic in any body of water, but Lake Tahoe is massive, with a surface area of 191 square miles. And over the past six years, it’s been very, very dry.

The downpour has filled lakes and reservoirs across the region. In the last two weeks alone, storms have dumped a combined 1.3 million acre-feet of water into the 154 largest reservoirs in the state. State hydrologists say those reservoirs are currently filled to about 97 percent of their capacity. That's an impressive change from the same date last year, when the ongoing drought left them at or below 50 percent of normal levels.

In some ways the storms were right on time, as experts had begun to worry about regional water supplies. But all extreme weather events—even welcome ones—have their downside. Flooding from surging rivers has forced thousands of residents to evacuate their homes.

Jana Frazier is a tour guide for the Department of Water Resources at Lake Oroville. She says that lake has risen more than 90 feet since December, swelling above the boat ramp and edging into the parking area.

“It’s really weird,” she told the Los Angeles Times. “We’ve been in low water for so long, it seems strange to drive across the dam and see it almost full.”

Officials say it’s still too soon to declare an official end to the drought, but more storms are expected over the coming week.