just found some cool info on this helmet - US 38th division and here is how they got their name
The spade-shaped shield bears the monogram "CY," which are the first letters of the name "Cyclone Division," approved on October 30, 1918. The history of the insignia originates with a natural disaster, described in the following story. Following a pleasant fall weather, December 1917 turned miserable with temperatures as low as 15 degrees above zero. For the south, that is COLD. For some reason, the 38th was late in getting its wool uniforms and overcoats, and there was much discomfort. Weather again played a trick when a cyclone struck Camp Shelby on April 17, 1918.
The passage of time may have somewhat dimmed the story of the cyclone as being perhaps a mythical basis for naming the 38th the Cyclone Division. It was no myth. The Gold Star Honor Role for Indiana for the years 1914 to 1918 was published in 1921 by the Indiana Historical Commission. It carries the name of Pvt. Vaughn D. Beekman, a native of Marion, Indiana, who enlisted in the Regular Army April 17, 1917. By subsequent transfers he came to Camp Shelby and was a member of the 152d Ambulance Company on April 17, 1918 when the cyclone hit and he was killed. He was buried in the I.O.O.F. Cemetery at Marion. Major General Robert L. Howze, when he assumed command of the 38th Division in August 1918, announced it would henceforth be called the Cyclone Division.