Question

but the plume of snow now blowing from the summit ridge was a bad sign: the montenegrins were struggling upward through ferocious wind.
in the sentence above, ferocious has the same or almost the same meaning as:
perpetual
typical
foggy
violent

Explanation:

"Ferocious" means fierce or violent. "Perpetual" means continuous, "typical" means normal, "foggy" means unclear. "Violent" is closest in meaning to "ferocious" as it also implies force and intensity.

Answer:

violent