Was Weather Behind the Record Times During the Windermere Crew Races?

On Saturday, May 6th both the men and women's crew broke long-term course records during the famed Windermere Cup races.  As noted by the Seattle Times:

The men’s winning time broke a 20-year-old course record set by Washington in the 1997 Cal dual regatta of 5:30.0. The women’s performance broke the 30-year-old record set by the Soviet Union national team in the 1987 Windermere Cup of 6:11.73.

Picture Courtesy of the University of Washington

What were the chances that both men's and women's teams would beat long-term records on the same day? Even the woman's coach Yasmin Farooq found it hard to understand.

Now I am the last one to detract from the stunning athleticism of the UW men and women's crew teams, some of whom I have had in my classes. They are fierce and disciplined athletes. But perhaps there was a meteorological/environmental factor that enhanced the times of both the Huskies and their competitors that day.

Let me explain.   

None of this was on my radar until I got a call  from someone from the Seattle police department (didn't note his name).  After assuring me that I wasn't in trouble, he told me that he was involved with the crew races and noted that the water seemed to be moving very fast (westward) during the competition in the Montlake cut (see map) ; he wondered whether that might have explained the records.  I mused that we have had a very wet spring and that there was a pulse of water moving into the rivers that weekend from melting mountain snow.  So maybe there was a connection.

The Windermere Cup Crew Races occur upstream of and in the Montlake Cut, a narrow passage between Lake Washington to the east and Lake Union to the west (red oval)

I told I knew who to call:  Larry Schick, lead meteorologist of the U.S. Army Corps of Engineers (USACE) in Seattle.  USACE runs the Hiram M. Chittenden Locks, which controls the water levels in Lake Union and Washington.  Larry was very helpful, and engaged the help of a hydrologist colleague, Adam Price.

The "plumbing"  of the region is relatively simple.  Most of the water that enters Lake Washington does so through the Cedar River (red oval below); that water then flows through the very narrow Montlake Cut (red oval above) into Lake Union and flows westward through the Locks before entering Puget Sound.  The outflow through the Locks and the inflow in the Cedar control the water levels in Lakes Union and Washington (there are minor rivers/streams flowing into the Lake as well).  Generally, the Corps keeps Lake Washington at around 20 feet during the winter and 22 feet in late spring.

This has been a exceptionally wet spring and thus the Army Corps has had to pass a lot of water through the Locks, resulting in strong westward flow in the Montlake cut (the race venue)

However,  the passage of a wet, warm front in early May upped the ante--it not only provided lots of rain, but also melted the bountiful snow in the Cascades.  As a result, the Cedar River surged, as shown by USGS Daily Discharge Data at Renton.  Blue is the actual this month and the orange triangles are normal,  The flow was WAY above normal on May 6th, reaching around 1800 cubic feet per second.  In fact, this was the greatest flow on record at that location on the that date.

According to USACE hydrologist, Adam Price, on race day the Lake Washington level was fairly stable and the Corps maintained an average release rate of 2800 cubic feet per second, enough to balance the Cedar and minor river inflows.  He told me that this was a very high outflow rate in May.   Using the 2800 cubic feet per second number and simple calculations, he determined the flow speed up the narrow Montlake Cut, finding unusually large outflow.  He did the same for normal May flow (850 cfs).   The result demonstrated that the boats were sped up considerably by the strong current, reducing their travel time by roughly 6 seconds.

So the wet spring and rapid warm up  resulted in increased flows that substantially reduced the travel time down the cut, and may have explained (at least partially), the records broken that day.

Interesting, the date of the previous Windermere Cup men's record (May 3, 1997) was also a period of unusually strong flow from the Cedar River into Lake Washington (see below).

The bottom line of all this is that it is possible that a wet spring and rapid snowmelt led to strong flow along the Windermere Cup race course that might have shortened the travel time appreciably.  

And it is only a rumor that the Husky Crew team has suggested that the US Army Corps of Engineers do a rapid release of water during the first Saturday of May 2018 😊