I understand. I live in Massachusetts so I know what last winter was like. Luckily I lived in an apartment and a condo this winter, so I didn’t actually have to shovel anything. The staff at the two complexes did clear a lot but they had fairly heavy machinery to do it.
The US Army in its’ wisdom doesn’t use flamethrowers anymore (real easy for the enemy to shoot the operator or the tank, causing friendly fire [heh heh] problems.) They use rocket launchers that fire napalm/phosphorous shells.
Also, from their FAQ it looks like they use a car fuel injection pump powered from aircraft model grade 12V (3S) Li-poly batteries.
Could be coupled with fuel injection valves for computer-controlled pyrotechnic displays (or a hardcore fixed area-denial defense system).
For the computer controlled flames, alcohol with dissolved pyrotechnic colorants could allow for making colored flame sequences. Bonus points for DMX512 protocol control.
The stream that flows through my yard provides drinking water to the town of Newark, DE, home of the University of Delaware and 30,000 other folks. I use my flamethrower to control invasive exotic pests on the property without recourse to toxic herbicides. Bonus, lesser celandine is edible when roasted!
Roundup ™ is a greater threat to you than flamethrowers, but we humans aren’t real great at risk analysis.
Edit: OK I apologize for being late to the party! You guys had it covered already…
Flamethrowers were deprecated for a number of reasons, but operators getting blown up by a tank rupture wasn’t really one of them. The pressurized propellant was non-flammable, and the fuel itself was tricky to ignite.