The University Record, November 5, 1997

El Nino cycle, Great Lakes weather linked, researchers say

El Nino may cause Great Lakes waves to reach an all-time high in intensity, researchers say. File photo

By Adam Marcus
College of Engineering

Most people associate El Nino with unusually good fishing on the West coast and warmer-than-usual winters in the East. Few links have been drawn between the periodic weather phenomenon and the middle of the countryÑuntil now, that is.

New climatological research by a pair of U-M engineers suggests that peaks in the El Nino cycle correspond with surges in storm strength, water levels and destruction on the shores of the Great Lakes. Moreover, because of the intensity of the current El Nino, residents of the Great Lakes region should consider bracing for what could be one of the most destructive storm seasons on record.

Guy and Lorelle Meadows, researchers in the Department of Naval Architecture and Marine Engineering, have found a correlation between El Nino years and elevated storm wave energies in the Great Lakes. "It's ongoing research. We're still trying to figur e out the total impact of this," says Lorelle Meadows, a research associate.

Even so, they say, the correlation appears to be quite strong. "Wave conditions on the Great Lakes, if we are right, may reach an all-time high in terms of their intensity," says Guy Meadows, associate professor of naval architecture and marine engineer ing.

The researchers derived the correlation by overlaying decades of Great Lakes storm data and water level fluctuations and comparing the results with El Nino strengths and dates. The result is a well-tracked pair of curves that seem to fluctuate in lock-s tep with each other. Great Lakes storm damage occurs when wave energies are high and water levels are on the rise. These coupled events seem to follow major El Nino episodes.

The scientists are not certain how El Nino influences Midwestern weather. However, one explanation is most likely: El Nino currents heat up the Pacific Ocean, spawning more frequent, stronger storms. Evidence suggests that these storms take paths over the Midwest, thus imparting a more direct impact on the Great Lakes basin than during normal years. This in turn leads to increased storminess and more powerful waves, which, in combination with high water levels, can be devastating to coastal areas.

In 1984 and 1985, storms caused some $130 million damage to the Great Lakes region. That period immediately followed the strongest El Nino in the last 20 years, according to the researchers.