This means that they go to high enough latitudes where the Van Allen belts are both radially thinner and lower in altitude, a double whammy.
Less scattering, more exposure to the belts themselves. Not to mention an activated SAA or the compression of the magnetosphere by a big CME that could be here in a day.

If you go back to this link, you'll see hard protons were way up for about a day, and actually increased after I posted the link previously.

http://sec.noaa.gov/rt_plots/pro_3d.html

Id say this means that a big CME is shocking the solar wind but the main front is no longer headed directly towards Earth. There are still HE Protons above quiescent levels being measured, so it's probably still there going strong, just not in our direction.

I'll tell you what, with conventional shielding, I'd not wan't to be loking down on the northern lights.