Bonus clues for the lost, confused, or desperate.

ACROSS
White stuff on the ground; see it in crazy felon's lawn. (6, 4)
The answer is FALLEN SNOW, an anagram of felon's lawn.
12 Bad housing you get when you take the pea off a downturn. (4)
The answer is SLUM: bad housing; take the pea (P) off a downturn SLUM(P)
26 The inevitable result of dealing with 1 across found in bellyaching backtalk. (6, 4)
The answer is ACHING BACK, which you get from shoveling fallen snow, as found in bellyACHING BACKtalk.

DOWN
Adam's green Christmas pet is balsam+short rd. + energy flow + really good grade. (5, 4)
The answer is FIRST CHIA: Adam's green Christmas pet is balsam (FIR) + short rd. (ST) + energy
flow (CHI) + really good grade (A)
16 Planetarium or composer's name sounds like a call for attention--or horse fodder--and the word for loud dissonance. (5)
The answer is Haydn: the name of both a composer and planetarium; a call for attention (HEY) or horse fodder (HAY) and the word for loud dissonance (DIN).
18 Skating knee-breaker found deep amidst Boston yams. (5)
The answer is TONYA (as in Harding) found deep amidst BosTON YAms.

Back to the damned puzzle