Frequently Asked Questions
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 multibeam 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. The lake level of Crater Lake fluctuates according to the climate.
The magnificent intense blue of Crater Lake is due to its great depth and clarity. Sunlight is able to penetrate deep into the water. The depth absorbs many of the longer rays and reflecting the shorter rays of the white light spectrum. Red light is the longest wavelength, thus gets absorbed. Violet and blue light are the shortest wavelengths, thus get scattered and reflected back to us, causing the lake to be its famous Crater Lake blue. The spectrum of the lake color changes from deep blue (31-46 m, or 100-150 ft) to light blue (<31 m, or 100 ft) to green (<15 m, or 50 ft) to yellow (<9 m, or 30 ft).
Although snow occupies Crater Lake National Park thoughout 8 months of the year (average annual snowfall is 14 m, or 533 in), the lake rarely freezes over. The last recorded year in which the lake froze over was in 1949, a very long, cold winter. 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 is air quality in the area?
Crater Lake National Park has some of the cleanest air in the United States. On clear mornings, one can see as far as 241 km (150 mi). The clean air allows spectacular views of the surrounding landscapes of Klamath Basin and the Cascades. Such views include Mount Shasta to the south and Three Sisters to the north; both are over 170 km (100 mi).
Have you seen the wrecked helicopter that crashed and sank into Crater Lake about three years ago with two people aboard?
No, the scientists did not see any evidence of the helicopter, probably because the helicopter hit the lake at full cruise speed. This caused the helicopter to break up into many small pieces and sink to the bottom. The Park Service reported that there wasn't any parts found bigger than the size of a basketball.