Use the verb paralyze to describe something that makes it impossible to move or function, like a snowstorm that threatens to paralyze a city.
Accent the first syllable in paralyze: "PA-ruh-lies." Until 1805, the only way to paralyze someone was physically — the word was used to indicate that a person had lost the ability to move their body, often as a result of an accident of illness. More recently, the definition has widened to include figurative uses like being "paralyzed by fear." It doesn't mean you are literally immobilized — just that you are so scared, it feels that way.