Polish television TVP is showing video from crash site now.
Here’s what TVP has;
http://translate.google.com/translate?hl=en&sl=pl&u=http://www.tvp.pl/&ei=njbAS9T0FsL48Ab62v3zCA&sa=X&oi=translate&ct=result&resnum=1&ved=0CBwQ7gEwAA&prev=/search%3Fq%3DTVP%2BPoland%26hl%3Den%26prmd%3Dn
( Sorry if link doesn’t work )
They say the cause may be dense fog.