HIGHS are sometimes reinforced and this results in what is called a
stagnant HIGH. A good illustration of such a slow moving HIGH and its
consequences occurred during the last week of January, 1922.
A surge of cold air from Alberta or farther north reached the
international boundary January 21st and spread slowly eastward, reaching
the Great Lakes on the 24th and the St. Lawrence Valley two days later.
Then seemingly it halted or moved slowly westward, retrograding. In
three days, that is, on the 29th, the centre of the HIGH was apparently
500 miles _west_ of where it had been on the 27th. After the 29th it
followed a normal track, moving slowly southeast, reaching the Atlantic
near Long Island.
Meanwhile a depression on the south coast of Texas on the 25th, moved
across the Gulf of Mexico, passing over Southern Florida on the 27th and
advanced steadily northeast, reaching Cape Hatteras in 24 hours. Owing
to the presence of the anticyclone referred to above, the depression
recurved off Hatteras. The result was a memorable snow storm in Northern
Virginia and Maryland. At 8 p.m. January 27th, there had been a fall of
5 cms. (2 inches). Within the following twenty hours the average depth
in the city of Washington was 66 cms. (26 inches). The weight of the
snow caused the collapse of the roof of the Knickerbocker Theatre and
the death of 97 persons.
The total snowfall in various coast cities was:
Raleigh 24 cms.*
Richmond 48 "
Washington 71 "
Baltimore 67 "
Wilmington 46 "
Philadelphia 31 "
Trenton 27 "
New York 18 "
New Haven 8 "
Boston 1 "
*Note: To convert to inches multiply by 0.4.
The table shows clearly how the snow was formed. On the east side of the
LOW a stream of air, relatively warm, carried a load of water vapor,
approximately 13 grams in each cubic metre.
[Illustration: BASE MAP BY GOODE