Learn Hardcore Japanese: kyonen ha yuki ga takusan hurimasita.

The particle は marks 去年 (“last year”) as the topic of the sentence, so you could translate it literally as “As for last year…”. It tells the listener you’re talking about last year in particular (often implying a contrast with other years).

Why don’t we see に after 去年? Wouldn’t “in last year” be 去年に?

Many time words like 去年, 今日は, 明日 can act as adverbs without に. Here 去年 alone functions as “last year.” If you specifically want to mark a point in time rather than topic, you could say 去年に雪がたくさん降りました—it’s grammatically correct but less common when you’re making 去年 the topic.

Why is 雪 marked with が instead of を or は?

In 雪がたくさん降りました, the verb 降る (“to fall,” used for weather) takes the thing that falls (雪) as its subject, so you use が. を marks direct objects (not applicable here), and は would topicalize “snow” rather than simply identify it as what fell.

Could we say 雪はたくさん降りました instead?

You could, but 雪は would set up “snow” as the topic (“As for snow…”), which implies a contrast or follow-up comment. To state the simple fact “Snow fell a lot,” Japanese uses 雪が to mark the subject.

What’s the difference between 雪がたくさん降りました and たくさんの雪が降りました?

雪がたくさん降りました treats たくさん as an adverb modifying the verb 降りました (“fell a lot”).
たくさんの雪が降りました makes たくさんの雪 a noun phrase (“a lot of snow”) that falls.
Meaning-wise they’re almost identical, but the first emphasizes the manner/degree of falling, the second emphasizes the amount as a noun.

Why is たくさん positioned before 降りました rather than right before 雪?

Here たくさん is functioning as an adverb modifying 降りました, so it naturally comes immediately before the verb in Japanese (though you could also say たくさん雪が降りました with nearly the same sense).

Why do we use the verb 降る for snow?

In Japanese, weather phenomena like rain, snow, hail, etc., all “fall.” So you say 雨が降る (rain falls), 雪が降る (snow falls).

What’s the function of ました in 降りました?

ました is the polite past tense ending for verbs. The dictionary form 降る becomes 降ります (polite present/future) and then 降りました (polite past), meaning “(it) fell.”

Can we omit 去年は and just say 雪がたくさん降りました?

Yes—but then you haven’t specified when. Listeners will assume a contextually obvious time. If you want to state “last year,” you need 去年は (or simply 去年).

How do you ask “Did a lot of snow fall last year?” in Japanese?

Keep the same structure and add the question particle か at the end:
去年は雪がたくさん降りましたか？

Are there other ways to say “a lot” besides たくさん?

Yes. Common alternatives include:
• いっぱい (informal) – 去年は雪がいっぱい降りました。
• 多く (おおく, more formal) – 去年は雪が多く降りました。
• 大いに (おおいに, very formal) – 去年は雪が大いに降りました。