Mono Lake

Understand

History

Starting in 1941 the streams that fed Mono Lake were diverted for use by the city of Los Angeles. With a yearly evaporation rate of , the lake level quickly dropped, going from an elevation of 6,417 feet (1,956m) above sea level to a low point of 6,372 feet (1,942m) above sea level. The accompanying 31% loss of surface area and 50% loss of water volume had a devastating effect on the estimated two million birds that used the lake each year, as well as causing air quality problems due to the dust from the now-exposed lakebed. In 1994 a court ordered that the lake be returned to a level of 6,392 feet (1,948 m) above sea level.

Landscape

The lake is believed to have formed 760,000 years ago, although it may be a remnant of a larger lake that formed 1-3 million years ago, thus making it one of the oldest lakes in North America. It is a saline lake with no outlets, fed solely by runoff from the surrounding mountains. One unusual feature of the lake is its many tufa rock formations. These rock towers form when underwater springs rich in calcium mix with the waters of the lake, which are rich in carbonates. The resulting reaction forms limestone. Over time the buildup of limestone forms a tower, and with the drop in lake level the towers have become exposed.

Flora and fauna

Mono Lake is a noted bird-watching destination. Brine shrimp and brine fly larva in the water and brine flies on the shorelines provide abundant food for hungry migrants that stop to refuel before moving on. Although Negit Island has become land-bridged (and thus accessible to predators) due to lake level decrease, the area's islands remain important breeding areas for birds. Approximately 85% of the state's population of California gulls cross the Sierras each year to breed here, as do a significant portion of the state's snowy plovers. In addition, between 1.5 to 2 million eared grebes use the lake during migration each year, as do 80,000 Wilson's phalaropes, 60,000 red-necked phalaropes, and nearly 80 other species of waterbirds.

The lake's food chain begins with algae that bloom in summer months. This algae becomes food for the 4-6 trillion brine shrimp that inhabit the lake, as well as the brine flies that gather on the shoreline. In summer months these flies rise up in black clouds when approached, although luckily they aren't biting insects and thus are not a nuisance to humans.

Climate

With little more than desert scrub in the basin, there is no shelter from the elements.

Winds routinely rip through the basin in all seasons. Choking alkali dust clouds can be lifted out of basin by the winds. Usually, the wind direction sends these clouds out to the east away from the most visited parts, but there's no guarantee that the direction won't change and provide you with a much more intimate opportunity to study the clouds firsthand.

In winter, snow occasionally covers the ground. Chains may be required to get around the basin, and are frequently required to cross the passes to get in and out of the region. State Route 120 is closed just west of US 395 all winter (and often all spring), and is closed east of the South Tufa area for much of the winter too.

In summer, if the wind stops suddenly, a cold day can suddenly turn into a scorcher.

Get in

The primary access to Mono Lake is provided by Highway 395, which runs north and south along the Eastern Sierra. During the summer months the lake can also be reached from Yosemite National Park using Highway 120 (Tioga Pass), but this route closes with the year's first snowfall and doesn't re-open until the following May or June.

Fees and permits

There are no fees charged to visit Mono Lake.

Go next

• Lee Vining. Along the lake shore, this town offers services and information about the lake.
• Yosemite National Park. The Tioga Pass entrance to the park is just south of the lake, but is closed from the first snow until the roads can be cleared in the Spring (usually around May).