Why might sterilized foreign-exchange market intervention have a greater impact on the exchange rate in times of

Question:

Why might sterilized foreign-exchange market intervention have a greater impact on the in times of financial stress than in times of normal market conditions?

Exchange Rate
The value of one currency for the purpose of conversion to another. Exchange Rate means on any day, for purposes of determining the Dollar Equivalent of any currency other than Dollars, the rate at which such currency may be exchanged into Dollars...