A worldwide community photographing and learning about wildlife
Loxosceles sp.
Hairy, big, spider
Lived in my garage, dark place, and cold.
By the speed, silouette, habitat, and hair... most likely a recluse.
Because of your lacation, most likely:
arizonica, deserta
may exceptionally be: laetha, reclusa
in any case, avoid being bitten, ugly necrotic wound.