They went down in a hail of bullets.
This use of "a hail of" metaphorically implies that the bullets were as thick as hail in a storm -- which is to say, there were a lot of them. In the same way a "hail of opportunities" implies a there were many opportunities.
However, it's a particularly inelegant metaphor. You don't normally try to catch hail -- you want to avoid being struck by it. If you want to imply that she had so many opportunities she should have been able to take advantage of one of them, you should use a more welcoming metaphor like, "a shower of opportunities," or, "a wealth of opportunities," or, "a fertile field of opportunities," or something similar.
In my opinion it's unfair to ask an English learner to interpret an awkward metaphor like this, but what can you do?