Regarding 'toad-choker', a number of variants occur. All are Southern US in origin, and all refer to torrential rainfall. Use of the phrase is hyperbolic and humorous; the notion that toads (or frogs, see variants) actually drown in such rainfall would, in the areas where the phrase is used, be considered worth a chuckle in its own right — the phrase is not intended to be taken seriously, although undoubtedly the more courteous and circumspect of Southern speakers would briefly entertain the notion, if for no other reason than to put the person who might take the phrase seriously at their ease.
Some variants, collected from the popular press, along with the first dates of use found, and the region where the phrase was published or was said to have been used (the latter enclosed in square brackets):
toad-strangler Yorkville, South Carolina 1870
frog-strangler [Texas] 1892
toad frog strangler Pine Bluff, Arkansas 1902
bull frog choker Talladega, Alabama 1911
toad choker [Florida] 1927
frog choker Florida 1952
frog drowner Michigan 1953
toad drowner Indiana 1979
Although not represented in the first uses of the variants until 1979, Indiana was well-represented overall in the regions of use.
In the 'scientific', or at least systematic, 1962 The regional vocabulary of Texas, by Elmer Bagby Atwood, Atwood reports percentages of possible occurrences from field collections for various phrases denoting 'torrential rain':
For an unusually heavy rain that does not last very long, the most frequent expression is gully washer (37), followed by downpour (30), and cloudburst (19) (Map 89). Other less common terms (less than 5 per cent) are flood, flash flood, pourdown, and waterspout. A good many humorous phrases have a limited currency — from two to ten occurrrences each. Among these are chunk floater, chunk mover, frog strangler, dam buster, stump mover, trash floater, and toad strangler. Many others occur only once each, but may not necessarily be original: clod roller, cob floater, duck drencher, dumplin mover, and so on.
[Bold emphasis mine. For details of Atwood's methodology, see linked work.]