(KRON) -- The California Highway Patrol activated a Silver Alert overnight Tuesday after a man was reported missing from Sunnyvale more than four weeks ago. The alert is for Santa Clara, San Mateo and Alameda counties. Mack Giovanni, 90, is described by authorities as 5 feet 10 inches tall and weig hing 195 pounds. He has hazel eyes and white hair. It is unknown what clothing he was wearing at the time he went missing. Missing person Mack Giovanni (Photo: California Highway Patrol) Giovanni was last seen around 4 p.m. on Monday, March 2, in the area of Palm Court and Erica Drive in Sunnyvale. CHP believes that Giovanni is on foot. Anyone who sees Giovanni is asked to call 911. ...read more read less