May 10, 1980:
The volcano remained under clouds most of the day. Steam and ash emissions were visible once the weather cleared. Surveys of the bulge showed that the outward motion had slowed to less than three feet per day, about half the average rate for the previous two weeks. The low rate was later considered to be the result of an erroneous measurement. There were 20 earthquakes larger than magnitude 3.0 recorded, including 10 larger than 4.0.
If you click here, there are some cool pictures and a some more information from our friends at the Discovery Channel.