Glenn Rivers
EF1
On Nov 13th last year, a strong storm moved across the Great Lakes, and unlike many November storms, this one reserved its greatest fury for Lake Ontario. As the surface low retreated ENE into Quebec, a very tight pressure gradient in it's wake created a violent tempest over the lake that started from about 250° and veered only slowly through to about 290° over a period of about 12 hours. These winds were close to being parallel to the long axis of Lake Ontario for quite a while and created truly mountainous seas over the eastern portion of the lake.
According to archived ETA data, the 850mb winds behind the storm reached 70 knots. As cold air moved into the area, the air became several degrees colder than the lake temperature, creating an unstable layer from the surface up to perhaps 850mb over the lake and enhancing downward momentum transport. The result was 50 knot storm winds that persisted for hours at the surface, with probable 1 minute sustained speeds of near 60 knots.
By a great stroke of luck, NOAA had not retrieved its # 45012 discus buoy from the east end of the lake (to the NE of Rochester NY). The result was a remarkable data set that as far as I can tell, documented the most extreme sea state ever officially recorded in a freshwater environment anywhere on earth by a high quality instrument capable of producing high fidelity spectral measurements of wind waves!
Three separate measurements taken by the buoy over a 3 hour period when averaged produced a significant wave height of 23 feet! The most energetic part of the wave spectrum had a period of 10-11 seconds! A search of the 20 plus year long NDBC data set for the Great Lakes failed to produce a storm that had a 3 hour average significant wave height of 23 feet. I suspect that waves this large and larger have occurred on the other Great Lakes at other times, but unfortunately the buoys are usually taken out in early November, and not replaced until April or May. Many of the greatest storms over the Great Lakes occur when the buoys have been pulled out for the winter.
According to archived ETA data, the 850mb winds behind the storm reached 70 knots. As cold air moved into the area, the air became several degrees colder than the lake temperature, creating an unstable layer from the surface up to perhaps 850mb over the lake and enhancing downward momentum transport. The result was 50 knot storm winds that persisted for hours at the surface, with probable 1 minute sustained speeds of near 60 knots.
By a great stroke of luck, NOAA had not retrieved its # 45012 discus buoy from the east end of the lake (to the NE of Rochester NY). The result was a remarkable data set that as far as I can tell, documented the most extreme sea state ever officially recorded in a freshwater environment anywhere on earth by a high quality instrument capable of producing high fidelity spectral measurements of wind waves!
Three separate measurements taken by the buoy over a 3 hour period when averaged produced a significant wave height of 23 feet! The most energetic part of the wave spectrum had a period of 10-11 seconds! A search of the 20 plus year long NDBC data set for the Great Lakes failed to produce a storm that had a 3 hour average significant wave height of 23 feet. I suspect that waves this large and larger have occurred on the other Great Lakes at other times, but unfortunately the buoys are usually taken out in early November, and not replaced until April or May. Many of the greatest storms over the Great Lakes occur when the buoys have been pulled out for the winter.
