I'm not finding any Charles I[Isaac] Blizzard in any Virginia unit but I did find the following which might have exempted him due to age, if this is the correct Charles I. Blizzard.

1880 United States Federal Census
Name: Charles I. Blizzard
Home in 1880: Speedwell, Wythe, Virginia
Age: 63
Estimated Birth Year: abt 1817
Birthplace: North Carolina
Relation to Head of Household: Self (Head)
Spouse's Name: Sarah T.
Father's birthplace: North Carolina
Mother's birthplace: North Carolina
Occupation: Laborer
Marital Status: Married
Race: White
Gender: Male
House Number: 14226007
Household Members: Name Age
Charles I. Blizzard 63 laborer
Sarah T. Blizzard 36 wife [2nd?]
Margaret E. Blizzard 16 dau
John H. Blizzard 15 son laborer
Malinda C. Blizzard 13 dau
Thursa J. Blizzard 10 dau
William F. Blizzard 8 son
Amanda Blizzard 6 dau
Julia V. Blizzard 4 dau
Olive B. Blizzard 21 dau

JR