Short Wave blackout

Yesterday we experienced that the short wave suddenly became quiet. Today we can rad the following on SpaceWeather:

"MAJOR X-CLASS SOLAR FLARE (UPDATED): On Sept. 6th at 1202 UT, sunspot AR2673 unleashed a major X9.3-class solar flare--the strongest solar flare in more than a decade. X-rays and UV radiation from the blast ionized the top of Earth's atmosphere, causing a strong shortwave radio blackout over Europe, Africa and the Atlantic Ocean".

Interestingly we (I and a few fellow ham operators) had the blackout earlier, at around 09 UT, 11 local time. already an hour later at 12 local time (10 UT), the ionosphere and hence the short wave  were regaining the capability to forward our transmissions.

Here you can see a map on how the short wave around the world was impacted.

It still remains however, why we noticed this before it was supposed to happen?