Dear Ms. Jackson,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located a series titled Mount Saint Helens National Monument Records, 1980 - 1989 in the Records of the Forest Service (Record Group 95) that includes records concerning the immediate aftermath of the eruption. To access these records please contact the National Archives at Seattle (RW-SE) via email at firstname.lastname@example.org.
We also located Sound Recordings Relating to Mount Saint Helens (Mt. St. Helens), Washington , 1980 - 1984 and Moving Images Relating to Mount Saint Helens, Washington, 1980 - 1984 in Record Group 95 that may include recordings of the press conference on that date. To access these records, please contact the National Archives at College Park - Motion Pictures (RDSM) via email at email@example.com.
In addition, please contact the US Forest Service and the US Geological Survey to request any records relating to these events that still may be in their custody. Also, newspapers and local TV news organizations in the Portland, Oregon and Vancouver, Washington area may have files concerning the conference.
We searched online and located a photograph of the conference on a Flickr page maintained by the U.S. Forest Service- Pacific Northwest Region however no time was given in the title or captions.
We hope this information is helpful. Best of luck with your research