Extreme high tides predicted this week
June 25, 2008 · Updated 1:02 PM
"South Whidbey high tidesWednesday 6:05 a.m. 13.2 feetThursday 6:47 a.m. 13.4 feetFriday 7:11 a.m. 13.5 feetThe highest tides since 1987 are taking place this week and may pose a threat to waterfront property owners, particularly if the tides are combined with strong winds.A series of tides 13 feet or higher started this morning at 6:05 a.m. when a height of 13.2 feet was projected. The highest will take place Friday at 7:28 a.m. with a level of 13.5 feet. The highs occur in Saratoga Passage on Whidbey Island's east side. West side tides are somewhat lower.T.J. Harmon, Island County Emergency Services director, warned Tuesday that some fairly high winds were possible for Wednesday.Sneaker waves are possible, she said, alluding to waves that could crash across the front decks of homes close to the waterfront.Harmon sent a high tide warning by e-mail to the media and fire districts in Island County.High tides are typical this time of year, but the projected 13.5 feet Friday is the highest level in the Seattle area since 1987, according to the National Oceanic and Atmospheric Administration (NOAA). The extreme tides are caused by the alignment in space and in time of the maximum effects of several normal monthly and annual cycles in the tide, stated a NOAA news release. First, there was a full moon on Jan. 9. Second, on Jan. 10 there will be a perigee of the moon orbit in which the moon is closest to the earth in its monthly revolution around the earth. When perigee occurs within a day of the full or new moon, the effects are additive and the tides are a little higher as a result. A third, but less additive effect is the occurrence of perihelion, in which the earth is closest to the sun in its orbit during January.What causes high tides also plays a role in low tides, resulting in some extreme low tides this week. Tonight at 11:20 there will be a minus 3.3 tide, and minus tides will continue through Sunday. "