Washington State Depth of Freeze Map for 1949 and 1950 Winters
This map shows contours of measured depths of freeze as determined during the
extremely cold winters of 1949 and 1950 (source: letter correspondence from B.
Tremper, State Materials and Research Engineer to W.A. Bugge, Director of
Highways, dated, October
17, 1951). The freeze depths were measured in holes dug along the
edge of the main lanes during February 1949 and January and February 1950 (a
total of 401 holes). Some observations made by Highway Department
personnel during the winters of 1949 and 1950:
- The greatest freeze depths were observed in sandy or gravelly soils.
- Snow or ice cover substantially reduced the depth of the freeze.
- Most frost heaving was observed in the coastal areas (due to the higher
availability of water).
- Frost heaving was somewhat infrequent in Eastern Washington but more
severe when it did occur (again, this likely related to the availability of
water).
- A maximum differential heave of 225 mm (9 inches) was noted in District 2
(now the North Central Region).
- Silty sands showed the largest amount of ice lenses.
Measured Frost Depths for the
Winters of 1949 and 1950