You're monitoring the VaR model for a trading desk. Over the last 250 trading days, you noticed 6 exceptions where losses exceeded the 99% VaR. How would you explain this to the desk head, and is the model still usable?

你负责监控一个交易台的VaR模型，发现过去一年（250天）出现了6次损失超过99% VaR的情况。你会怎么跟交易主管解释这个结果？模型还能用吗？