Lilim moves forward and says, "I'll get her out of her comfort zone. If she and her lizards persist there, we are better at handling sleet storm I think."
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MA: She moves forward 30', putting her one square north of Erima.
SA: She casts sleet storm. The intersection is the corner of the proscenium thrust most northwards of the dais (yay, theater geek terms). That should encompass that entire northern area in uncomfortable snow and ice for Sourshen.