Total precipitation during the 1989 water year was about 94 percent of normal in both western Washington and eastern Washington. The total precipitation for the water year ranged between about 78 and 107 percent of normal throughout the State. Precipitation during September was the farthest below normal for a month when the monthly total was about 15 percent of normal in western Washington and about 19 percent of normal in eastern Washington. Monthly precipitation was the farthest above normal during November in western Washington, and during March in eastern Washington, when monthly totals were about 145 and 185 percent of normal, respectively.

Rainfall in western Washington was less than 75 percent of normal during the months of December, February, June, and September. It was near normal during October, January, April, May, and August, and was more than 125 percent of normal during November and March.

In eastern Washington, precipitation was less than 75 percent of normal during the months of October, December, January, June, July, and September. It was near normal during February and April, and was more than 125 percent of normal during November, March, May, and August.

The annual mean runoff in both western and eastern Washington during the 1989 water year was below normal.

The most significant floodflows of the 1989 water year occurred on October 16 and on November 5, 6 in western Washington streams. The areal extent of flooding on October 16 was limited; the Snoqualmie and Skykomish Rivers were most heavily affected, and peak flows at gaging stations on those streams had recurrence intervals of 5 to 10 years. Peak flows at gaging stations throughout western Washington during November 5, 6 high water had recurrence intervals generally ranging from one to 5 years. (A peak flow that has a recurrence interval of five years can be expected to be exceeded once in five years on the average.) The annual peak flows at most gaging stations in eastern Washington had recurrence intervals of one to two years.

Return to:
[Washington State Hydrology Menu] ...