Fog Cloud

Duration: 1 hour, Concentration
You create a 20 ft radius sphere of fog. The
sphere spreads around corners, and it's area
is heavily obscured. It lasts until a wind of
moderate speed disperses it.
At Higher Levels. When you cast this spell
using a spell slot of 2nd level or higher, the
radius of the fog increases by 20 ft for each
slot level above 1st.