There was a lot of snow in the streets last winter.(Past Indefinite) — Прошлой зимой на улицах было много снега.
The sentence is in the Past Indefinite that’s why we use was. And snow is uncountable that’s why we use the past form of the verb to be in singular.
There is a lot of snow in the streets this winter. (Present Indefinite).
Negative.
There wasn’t a lot of snow in the streets last winter.
Interrogative.
Was there a lot of snow in the streets last winter?
There was a lot of snow in the streets last winter, was not there?