The World Meteorological Organization (WMO) reported on January 22, 2010 that Mount Washington's world record had been broken. A wind gust of 253 mph during Typhoon Olivia on April 10, 1996, in Barrow Island, Australia has broken this record. A panel of WMO experts investigated the report, and this conclusion has been made after an extensive review of data, and an evaluation of the weather instruments used. I will decline to comment on why it took the WMO about 15 years to issue this report. (Oops... there I just did.)
The WMO Commission for Climatology provides more information about Global Weather and Climate Extremes at: http://wmo.asu.edu.