1. In 1912, the town of Knik, Alaska was destroyed by a massive rockslide on July 31st. The event, known as the Knik landslide, occurred when a large chunk of unstable rock on a nearby mountain gave way, burying the town and killing several people.

2. On July 31, 1937, the United States government established the Chugach National Forest in southcentral Alaska. This massive forest covers over 6 million acres of land and includes numerous glaciers, mountains, and rivers.

3. In 1953, the U.S. Army Corps of Engineers completed construction of the Alaska Highway. This historic route stretches from Dawson Creek, British Columbia, to Delta Junction, Alaska, covering over 1,500 miles of rugged terrain. The highway was built during World War II to provide a land route to Alaska, and today it remains one of the most scenic drives in North America.

4. On July 31, 1968, the city of Anchorage was struck by a magnitude 6.5 earthquake. The quake caused significant damage to buildings and infrastructure throughout the city, particularly in the downtown area. While there were no fatalities, thousands of residents were displaced from their homes.

5. In 1980, the massive eruption of Mount St. Helens in Washington state had a significant impact on Alaska as well. The eruption caused widespread ashfall across much of Alaska, disrupting air travel and forcing the closure of schools and businesses. The ash also posed a significant health risk to residents, as it can cause respiratory problems and other health issues.