Category Archives: Inquiries

Frequently Asked Questions

Frequently Asked Questions about Crater Lake

We asked a few of our members (many were naturalist rangers at Crater Lake) what were some of the most common questions asked by crater lake visitors.

Why is Crater Lake so blue?

The water is so blue because there is hardly anything else in it – just water. It’s not pure water, but it’s close. Water molecules with no sediments, algae, pesticides or pollution, will absorb all the colors of the spectrum except the blues. Those wavelengths will bounce back and make the water appear blue. The key is to have relatively pure water and lots of it. There has to be enough molecules to absorb all the other colors. (There are 4.6 trillion gallons of water in the lake, so it works really well.)

Does the crater lake ever freeze over?

Although snow occupies Crater Lake National Park throughout 8 months of the year (average annual snowfall is 14 m, or 533 in), the lake rarely freezes over. There have been only two reports of this ever happening. It was completely covered by ice from March 14 to mid May during the winter 1949 and four days in February, 1924. In April, 1983 about 95 percent of the lake froze. The immense depth of Crater Lake acts as a heat reservoir that absorbs and traps sunlight, maintaining the lake temperature at an average of 12.8 °C (55 °F) on the surface and 3.3 °C (38 °F) at the bottom throughout the year. The surface temperature fluctuates a bit, but the bottom temperature remains quite constant.

How far is it around Crater Lake?
33 miles.

Are there eagles at Crater Lake?

Bald Eagles are fairly common at Crater Lake during summer, but much larger numbers can be seen at the nearby Upper Klamath Lake National Wildlife Refuge. The winter eagle population may reach one thousand migrant birds.

How far down to the water?

The rim rises anywhere from 500′ to almost 2,000′ above the lake’s surface, creating a spectacular visual effect. The distance from the rim village area (the area of the Crater Lake Lodge) to the surface of the lake is approximately 900 feet.

How was Crater Lake formed?

The phrase “GREW, BLEW, FELL, and FILL” describes the process that created Crater Lake.

Grew – Mount Mazama was a large composite volcano that was built during the past 400,000 years by hundreds of smaller eruptions of lava flows. Mount Mazama rose to an approximate height of 3,700 m (12,000 ft) above sea level.

BLEW – About 7,700 years ago, Mount Mazama erupted catastrophically, blowing out about 50 km3 (12 mi3) of magma in a few days. The volcanic ash covered parts of the northwestern states, spreading as far as central Canada. Rare particles of Mazama ash have even been found in ancient ice from Greenland. The airfall pumice and ash covered a total surface area of more than 2,600,000 km2 (1,000,000 mi2) at least 1 mm thick. A volume of 42-54 km3 (10-13 mi3) of the mountaintop had disappeared. Where had all this mass gone? Did Mount Mazama blow its top off?

FELL – Mount Mazama did not blow its top off; it collapsed in on itself. As this enormous volume of magma was rapidly removed from the chamber to feed the climactic eruption, it created a huge void underneath the mountain. Leaving no support for this massive dome, the roof of the magma chamber collapsed, forming the bowl-shape depression known as a caldera.FILL – About 5,000 to 6,000 years ago, the accumulation of rain and snow filled the caldera. It took perhaps 250 years for the caldera to fill to its present-day lake level, which is maintained by a balance between precipitation and evaporation plus seepage.

How deep is Crater Lake?

Crater Lake is known to be the deepest lake in the United States and the seventh deepest in the world. The maximum lake depth of 589 m (1,932 ft) was established in 1959 by the USGS using sonar measurement. But since its primary input source is dependent upon the climate, lake level is subject to abrupt changes. The caldera is a bowl-shape depression of about 1,219 m (4,000 ft) deep.The maximum depth of Crater Lake recorded at the time of the July 2000 multi-beam survey was 594 m (1,949 ft). The lake level had an elevation of 1,883 m (6,178 ft) above sea level at the time of the survey.

What is the distance across Crater Lake?

Approximately 9 kilometers (5.6 miles). It’s maximum width is approximately 6.02 miles and it’s minimum width is approximately 4.54 miles.

When was Crater Lake established as a National Park?

Crater Lake: the 5th, 6th, or 7th park established? It depends on how you look at it. If you only consider existing national parks, Crater Lake could be numbered as high as the fifth national park. Crater Lake became #5 with the decommissioning of Mackinac Island and the absorption of General Grant into the current Kings Canyon National Park. If you allow General Grant to remain, we are #6 on the list. If you stick to the original list, regardless of present status, Crater Lake was the seventh national park to be established.

How much snow does Crater Lake get?

The average snowfall at Crater Lake is 533 inches every year. That’s about 45 feet. The greatest cumulative snowfall for one season was 879 inches (73 feet) the winter of 1932-33. The greatest depth on the ground at one time was 258 inches (21½ feet) the winter of 1983. Most of the snow usually melts by the beginning of August, although after particularly heavy seasons, there are drifts that fail to melt before the snows return again in the early Fall.