Grandfather clauses were designed to

The intent and effect of such rules was to prevent African-American former slaves and their descendants from voting, but without denying poor and illiterate whites the right to vote.

Explanation:

basically to stop blacks from voting without having to hard themselves like the white people have not meet the age requirement, but their father was a civil war hero for south, they they were allowed to vote.

mount st. helens in washington erupts, causing a massive avalanche and killing 57 people on this day in 1980. ash from the volcanic eruption fell as far away as minnesota. seismic activity at mount st. helens, which is 96 miles south of seattle, began on march 16.