No. 392] AN ABNORMAL WAVE IN LAKE ERIE. 655 
The first indication of any unusual disturbance was at 1.10 
P.M., when a small tornado struck the town of St. Clair, Mich. 
Trees were blown down by the hundreds, and about a dozen 
houses were seriously damaged. The wind was accompanied 
by a driving, soaking rain which lasted about thirty minutes. 
But the tornado was seemingly local in character, as the wind 
at Marine City, Lenox, and Memphis (near-by towns) was but a 
zephyr. It is doubtful whether this local stationary storm had 
any influence directly upon the meteorology of the surrounding 
country, although it may have started upper air currents, which 
might have produced results later, especially if it caused high 
westerly currents. 
According to Davis, thunderstorms are often caused in this 
way, when the higher members of westerly currents overrun 
the southerly winds for a considerable distance eastward of the 
line which separates the two winds at the surface of the earth. 
At 4.15 P.M., at Detroit, the first thunder of an approaching 
thunderstorm was heard, and at about 4.30 heavy rain began 
to fall, ending at 6.40 P.M. 
At Toledo the wind had been generally southwest until 4.30 
P.M., when a squall suddenly increased it to a gale from the 
northwest. The flagstaff halyards at the observing station 
were blown loose and caught around the cups of the anemom- 
eter, holding them fast and causing a loss of record until 
7.50 P.M. It is estimated that the wind attained a velocity of 
forty-two miles per hour, with an extreme of sixty, during the 
first ten minutes of the squall. The barometer fell slowly 
until 4.20 P.M., then rose suddenly 0.07 inches and remained 
nearly stationary the rest of the day. The temperature rose 
rapidly during the day; just before the squall it registered 93°, 
but fell to 71° F. from 4.30 to 5 P.M. 
At Point Pelee Island the wind had been blowing from the 
east and southeast since noon of the 18th. At about 5 P.M. 
on the 19th a squall increased its velocity from sixteen to 
twenty-four miles per hour, and changed, oppositely, its direc- 
tion from east to west, whence it gradually changed to north- 
west, to northeast, and back to east. Accompanying the squall 
was the thunderstorm. 
