REMARKABLE STORM AT NEW ORLEANS. 43 



METEOROLOGY. 



REMARKABLE STORM AT NEW ORLEANS. 



THEO. V. VAN HEUSEN, SIGNAL CORPS, U. S. A. 



On the 1 6th instant there prevailed at this city and immediate vicinity a 

 severe thunder storm, characterized by some very remarkable features, a brief 

 description of which may be acceptable to those of your readers who take an in- 

 terest in the meteorological department of your magazine. 



During the day in question the atmospheric conditions were such as almost 

 invariably precede thunder storms. The temperature rose to 85 °, the humidity 

 was above normal (there being present in the atmosphere during the day from 

 6.25 to 8.35 grains of vapor to each cubic foot of air), and gentle winds, blowing 

 from the marshes to the southward, prevailed. 



At 5 p. m. there was observed in the western sky a cumulo-stratus cloud, 

 whose apex had an altitude of about 30 and the base of which extended along 

 the horizon some 45 °. While this base appeared to remain stationary, the con- 

 vex upper portion of the cloud, which was of a deep brown color with white and 

 curling edges, gradually extended itself until it had overspread two-thirds of the 

 sky. The wind at this time had moderated to a light breeze blowing variably 

 from south to east, and the air was oppressively warm and moist. At 5:30 p. m., 

 before any discharge of electricity had taken place, huge scattering drops of rain 

 commenced falling, striking the pavement with a snapping noise like the cracking 

 of a whip, and spattering to the size of a saucer. A moment later there occurred 

 a vivid flash of zig-zag lightning, instantly followed by a crashing peal of thunder 

 and rain descending in torrents. This continued until 5:55 p. m., when a shower 

 of hail commenced falling, which, for size and quantity of the hailstones, is said to 

 have exceeded any phenomenon of the kind heretofore experienced in this section 

 of the country. During a period of five minutes or more the ground was white 

 with hailstones, which, upon measurement, were found to be from one to five 

 inches in circumference. At 6:20 p. m., or after a continuance for the remarka- 

 bly long period of twenty-five minutes, the hail ceased and rain, descending in 

 sheets, followed unt'l 7:50 p. m. From 6:40 p. m. to 6:45 p. m., there was a sec- 

 ond shower of small hail mingled with the rain. 



The electrical display during the storm was of unusual magnificence. The 

 lightning flashes were intensely brilliant, being almost exclusively of the zig-zag 

 order — showing the conducting power of the different portions of the atmosphere 

 to be very unequal — and followed each other in rapid succession, while the peals 

 of thunder were long, loud and incessant. 



