in regular mode they either do the single stomp, triple stomp, or fire stomp (EDIT - that fire stomp is what kills me most because I would activate realm shift for the projectile and throw all the timing off while she still in the air
)
in NG+ Sigrun will randomly choose each one so you have to know her rhythm or she will catch you
ive actually had her jump DIRECTLY after me blocking one of her wing swipes. In NG+ she basically will cheat you unless you dodge her outright
blocking/parry is ineffective in harder difficulties not just with valks but with all monsters especially Viken/Travelers