I don't know the numbers on actual dose for something like this, but I'd expect that it's "elevated radiation risk" in much the same way that getting a CT is. If you get scanned 10,000 times, there's a pretty good chance you'll die from cancer, but mostly it's just a slight statistical increase in your odds.
According to noaa there was an S2 Solar Radiations Storm and in the description for S2 it says:
> Biological: Passengers and crew in high-flying aircraft at high latitudes may be exposed to elevated radiation risk.
But the scale goes up to S5 and it the radiation will be higher for Austronauts, and for high flying aircrafts there is always a "may" attached.