you have the maximal thunderstorm frequency 
in summer with one maximum over Florida and 
the other over New Mexico, the first being 
characterized by practically no hail, but by much 
rain and low cloud base. In the other maximum 
you have rather little precipitation reaching the 
ground, with the cloud base more than 3500 m 
ab. s.-l. I think, on an average the cloud base is 
generally higher than Mount Sandia at Albu- 
querque, and yet hail reaches the valley, which 
is 1500 m ab. s.-l. My explanation, when I tell 
my students about these things, is that in Florida 
the hailstones exist probably high up in the 
cloud, but they melt before reaching the ground 
because there is constant condensation on them 
all the time, almost down to the final melting. 
In the New Mexico region they fall through dry 
air. They may evaporate, but they do not melt 
beeause they keep cool. Those principles would 
DISCUSSION 
probably, on the whole, apply to all the storms 
in the tropics, and I thought it was generally 
recognized that there was no hail within the 
equatorial region. The really devastating hail is 
in central Europe, in Switzerland, and certain 
parts of the United States, but not in Florida. 
And then as to the shear and the high winds 
aloft, in Florida there are no such high winds 
aloft in summer. The jet may reach down to the 
northern part of New Mexico, which has a 
higher latitude. So jet and hail may have a com- 
mon basis, but there need not be any direct con- 
nection between them. 
Dr. C. J. Todd—F. H. Ludlam pointed out 
(Nubila, 1, p. 1, 1958) that the fall velocity 
of hailstones of radius of one centimeter or 
larger at O°C is so fast that they should reach 
the ground with little loss of radius even in hot 
weather. 
