If you are interested, have a look at:
Ionospheric Prediction Service
There is an HF warning current, recommending Lower Freq Bands:
DEGRADED HF PROPAGATION CONDITIONS EXPECTED
FROM 20 JANUARY 2005
IF COMMS DIFFICULTIES EXPERIENCED TRY A LOWER FREQUENCY BAND
They also have a couple of pages where you can enter: Departure, Destination and the HF Freqs, and it will tell you where you can get comms and where you can't , and on what Freq (or black holes where you won't) given the current solar activity.
PAF