Questions & Answers about Lavinen var för snabb för att undvika.
Why does the word för appear twice in this sentence?
This is the standard Swedish construction for "too [adjective] to [verb]". The first för means "too" (för snabb = "too fast"). The second för belongs to the phrase för att, which means "to" or "in order to". Literally, the structure translates as "too fast in order to avoid".
Since the avalanche isn't avoiding anything itself, shouldn't it be the passive form undvikas?
You can actually use either! Just like in English ("too fast to avoid"), it is very common to use the active infinitive undvika here, even though the avalanche is the thing being avoided. However, using the passive s-form undvikas ("to be avoided") is also perfectly correct and sounds very natural.
Why do we use snabb here instead of snabbt?
The adjective has to agree with the noun it describes. Because en lavin is an en-word, the adjective takes the basic form snabb. If the subject were an ett-word, like tåget (the train), it would be tåget var för snabbt.
How is the verb undvika built?
It is made up of the prefix und- (which often implies moving "away" or "escaping") and the verb vika (to fold, yield, or give way). Put together, undvika means "to avoid" or "to evade".