45 Temperature of Crater Lake

The Geology and Petrography of Crater Lake National Park, 1902




Fig. 2.—Thermometer and attachments used at Crater Lake.

Among those who visited Crater Lake with the Mazamas in 1896 was Dr. Barton W. Evermann, of the United States Fish Commission, who made some observations on its temperature. He reported that on “August 22, at a station about 2-1/4 miles east from the southeast corner of Wizard Island * * * the surface temperature was 61°; at a depth of 555 feet, 39°; at 1,040 feet, 41°; and at 1,623 feet, which was at the bottom, 46°.”a He further remarks that “If there be no error in our observations, it seems certain that the waters of Crater Lake are still receiving heat from the rocks upon which they rest.”b His observations were made with a Negretti-Zambra deep-sea thermometer, tripped by means of a propeller. Dr. Evermann says:b

“The only possible source of error which has yet suggested itself is that the propeller may not always have worked properly. It is possible that, in some cases, when we began hauling up the thermometer, the propeller failed to reverse until some moments later, in which case the reading would be that for some depth other than the one desired. This is a possibility, though it seems to me improbable. The observations should be carefully repeated before the conclusions suggested by the results should be accepted.”

aMazama, Vol. I, No, 2, p. 232.
bOp. cit., p. 234.

The volcanic rocks of Wizard Island, although recent, are sufficiently old to have completely cooled off. There are no visible fumaroles or hot springs anywhere about the lake to indicate local remnants of volcanic heat, and it was not expected that the bottom water would be warmer than the main body of the lake. Dr. Evermann’s observations suggest that the point of latest volcanic activity on the floor of the lake is now beneath its surface and possibly near one of the two cones located by the soundings. He made only one series of observations to depths beyond 500 feet.

To settle this matter, if possible, several thermometers of the common form, but with thick glass jackets to withstand pressure, were obtained from James Green, of Brooklyn, and a reel having a rapid winding attachment was prepared for their manipulation. Hard-drawn tinned-steel wire, No. .042, was found best suited to the work. Each thermometer was placed in a protecting brass tube (A in fig. 2), closed by a perforated rubber cork, and placed in a cylindrical bucket B, 3-1/4 inches in diameter, having an upward opening valve C at each end to allow the water to pass through while the bucket was descending, but to hold it confined while ascending, and thus not only preserve the temperature of the thermometer but at the same time to furnish a sample of the water from any depth desired. The stone D and double hook E were released from the suspending bar F at the end of the wire when the bottom was struck. Loops were placed on the wire at intervals of 500 feet, so that several thermometers could be sent down at the same time. After lowering the thermometers they were moved vigorously up and down for a few minutes to fill each cylinder with water. They were allowed to remain there for half an hour to make it sure that the thermometer in each ease had acquired the temperature of the place. The thermometers were raised as rapidly as possible and read at the surface. The thermometer from a depth of over 1,900 feet reached the surface and was read in less than 4 minutes. Experiments showed that by changing the water in the cylinder as noted above the thermometer readily acquired the water’s temperature, but with valves closed and water confined in the cylinder, as when ascending rapidly, the thermometer was amply protected from the influence of the higher temperature of the surface waters.

In order to eliminate the chances of failure as far as possible we obtained from the United States Fish Commission, through the kindness of Dr. Evermann, a Negretti-Zambra deep-sea thermometer, tripped by a messenger sent down the wire. He furnished us also the necessary apparatus for using the thermometer. This thermometer and the ordinary form noted above were sent down together a number of times, and invariably agreed when brought to the surface. The Negretti-Zambra several times allowed the messenger to pass the clip without reversing, but when registered there is no danger of change by surface temperature. The two forms of thermometers were generally used on the same wire 500 feet apart.

Observations were made at three widely separated points to a depth of over 1,300 feet, and the results are given in the accompanying table. The temperature of the lake everywhere below a depth of 300 feet is approximately 39°, and the bottom contains no appreciable volcanic heat.

Temperature of Crater Lake.
Depth. 1. 2. 3. 4. 5.











aCommon form of thermometer with thick glass jacket inclosed in brass tube and suspended in bucket 3-1/4 by 12 inches.

bNegretti-Zambra deep-sea thermometer.

No. 1. July 8, 1901, 8 a. m., 1/2 mile toward island from Eagle Cove. Thermometer down 30 minutes; raised from 500 feet in 2 minutes.

No. 2. July 8, 1901, 9.40 a. m., 1/2 mile toward island from Eagle Cove. Both common form and Negretti-Zambra sent down, but messenger failed to trip Negretti-Zambra. Down 30 minutes; raised in 4 minutes.

No. 3. July 8, 1901, 10.50 a. m., 1/4 mile toward island from Eagle Cove. Thermometer down 30 minutes; raised in 5 minutes from 1,306 feet.

No. 4. July 17, 1901, 8.40 a. m. Near deepest part of lake, where line from Dutton Cliff to Cleetwood Cove crosses line from top of Cinder Cone, on Wizard Island, to Cloud Cap. Put common form at end of wire and Negretti-Zambra 500 feet higher. Sent common form down first to 1,000 feet; left down one-half hour and raised in 4 minutes; then sent to bottom—1,942 feet—with Negretti-Zambra at 1,442 feet, and bottom one came up in 8 minutes.

No. 5. July 19, 1901, 9.10 a. m., 1/4 mile south of Cleetwood Cove. Surface temperature, 52°; but at 10.40 it was raised to 54°. At 972 feet Negretti-Zambra failed to trip and register. This last series was observed by James Storrs and E. W. Herchberger.

It may be noted also that Crater Lake, although over 6,000 feet above the sea, does not freeze over in winter, as do the Klamath lakes, at a much lower level, upon the eastern side of the mountain. Mr. E. W. Herchberger, a trapper, saw Crater Lake March 15, 1895, without ice. The winter was very cold. At the same time Diamond Lake and the Klamath lakes were covered with thick ice. He saw the lake half a dozen other times in the depth of winter from the east and never noted any ice. On February 18, 1900, he saw the lake from the west and noted ice over the shallow water between the island and the west shore, but none elsewhere. Although the lake is always open, Mr. Herchberger never saw any water birds on the lake in the winter.

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