Interesting. Astrid Ogilvie (Weather and Witchcraft in the Sagas of Icelanders) writes:
There are many accounts of magic spells inflicted through the act of speaking, including chants, libels and insulting phrases (söngvar, ákvæði, áhrinsorð, níð, and fordæðuskapur). The words of some speakers are charged with a particular power, as in the words of Þorbjörg aided by the Varðlokur recited by Guðríður in Eiríks saga rauða. One type of divination is also at work here, the forspá, as supposed to the discovery of hidden knowledge (eftirryni).
She further writes:
However, witches’ storms could sometimes be ameliorated by equally powerful counter spells.
In the case of Ósvífur and his companions, they are given what might be termed a magical weather warning; but the warning is heeded, and no one suffers serious injury or death. The incident involving weather magic in Laxdæla saga has more serious consequences, however.
I am thinking that this is connected to my dream of the Jotun who did alot of smashing (in which I shared the warning of some event that I could not prevent in the dream) and the recent EF5 tornado in Oklahoma. I'm pretty sure my Jotun dream was meant to communicate hidden information to me.
I didn't conjure up the tornado.