Effects work must be planned and executed in such a way that any risk to the safety of staff, artistes and the public is kept under control.
Using real flames involves significant safety precautions and need to be carefully controlled to ensure they behave as intended during filming.
Competence, communication and planning are vital to those who intend to use explosives, pyrotechnic or fire effects.
For smoke effects on Productions a vetted contractor should be used where possible.
Whilst there are snow effects you can buy and use yourself you should always, where possible, use a competent contractor to manage them for you.