~くらい ~ぐらい could mean a darn lot of things like "about"/"at least"/"enough"/"such", etc.. depending on the situation (Basically, it means "about")
1. There was an earthquake strong enough to make the shelf fall.
2. When it becomes a night around here, it gets so quiet that it feels lonely.
3. 木村さん (Kimura-san most likely) couldn't go to the long-awaited trip, and he made such a poor, disappointed face.
4. I was so hungry that I couldn't bare it anymore. (literally : "at least that hungry")
5. I wish that you at least greet someone when you meet him.
I'll give you an easier example (those were somewhat complex for someone who doesn't know the grammar):
~何年ぐらい勉強をしていましたか? (~About how many years have you studied ?) / Although どのぐらい would be more natural, you can still ask like this ^^