1930s Chicago dust storm

Dear Tom,
I read a book about the 1930s Dust Bowl, “The Worst Hard Time.”
It mentions a dust storm that impacted Chicago.
What exactly happened here?
—Mike Rehor
Dear Mike,
During the 1930s, Chicago along with the Plains and Midwest were in the
grasp of a combination of heat and drought known as the “Dust Bowl.” These
summers were characterized by searing heat and blowing dust, and it was
during this period that Chicago recorded many of its highest temperatures.
The dust storm of May 10-11, 1934, was remarkable. With northwest winds
gusting to more than 50 m.p.h. and relative humidity levels at a record low
13 percent, clouds of dust swept into Chicago, reducing the Visibility to
less than one mile in many areas. Officially, seven days in the 90s were
logged in May 1934 including a scorching 98 degree high on May 31.
