2 problems with the hail:

 

i trained my snover at Dragon den with snow warning and i've seen if my Snover dies and i throw another pokemon the hail hit 1 time my own pokemon and 2 times ennemy

And second isn't important but if my snover dies and ennemy too with the hail , i gain 0 exp ( probably normal) but also 0 pokedollar :/

if my Snover dies and i throw another pokemon the hail hit 1 time my own pokemon and 2 times ennemy

It happens because every weather condition is a 5 turn event, even if the pokémon that caused the weather change faints, they will be up untill the 5th weather turn is over

if my snover dies and ennemy too with the hail , i gain 0 exp ( probably normal) but also 0 pokedollar :/

I reported this one to the developer in the staff area, so it should get reviewed soon.