Like most desert locales, Lake Mead National Recreation Area south of Las Vegas doesn't receive a lot of rain, but when rain does fall, it can sometimes be too much of a good thing. A flash flood on Monday afternoon caused nearly $1 million of damage at Callville Bay, and that area and the Callville Bay Access Road have been temporarily closed to all park visitors while clean-up and repairs are underway. That process is expected to take at least several days.

According to park spokesman Andrew Munoz, the storms brought a wall of water about 10 feet high down Callville Wash; the flash flood caused significant damage to the marina and knocked out electricity to the entire area. The water was powerful enough to move 10,000-pound concrete blocks used to anchor the marina.

There was good news for owners of boats moored at the marina—no privately-owned vessels were damaged—but park and concessioner facilities didn't fare as well. Damage assessment teams from the National Park Service and Forever Resorts will be working this week to assess the storm damage and provide accurate cost figures. Preliminarily estimates are near $1 million in damage.

NV Energy is working to restore power to the area, but that process may take up to a week.

Further up the lake at Echo Bay, the launch ramp is closed due to the dirt access road to that location being washed out. Maintenance crews should have access restored by the end of the week. All other services at Echo Bay including the marina, store and trailer village are open.

Temple Bar and Hemenway Harbor launch ramps are open and full services are available from those marinas, and Lake Mead RV Village is open.

Two key roads in the park were closed for several hours on Monday afternoon due to the storms. By late afternoon flash flooding and debris on roadways had caused officials to close access to the park at Boulder Beach, Lake Mead Parkway, Lake Mead Boulevard and the Overton entrances. The two key routes on the north side of the lake, Lakeshore Road and Northshore Road, were closed to through traffic for several hours.

Lakeshore Road had reopened before dusk on Monday, and Northshore Road and was reopened to traffic later than night.

If you're not familiar with the locations mentioned above, you can download maps of the park from the park website.

Anyone planning a visit to Callville Bay is being advised to check the park website for current conditions; updates are also posted on the park's Twitter site at http://twitter.com/LakeMeadNRA