Date: Wednesday, September 24, 2025
Time: 9:00 a.m. – 1:00 p.m.
Location: Meet at MNHC, travel by MNHC bus
Cost: $40 MNHC and GLM Chapter members/$60 non-members

See Glacial Lake Missoula’s seasonal calendar recorded in sediment with geologist Jim Shelden!

Varves are annual sediment depositions, often recording seasons in differently colored bands. Darker bands are deposited in winter as organic matter settles, and lighter bands are deposited in the summer as glacial flour and run-off sediments drift to the lake bed. Varves also give a minimum depth of water greater than 300 feet. Glacial lake varves are often beautifully preserved.

The Ninemile varves are crucial to understanding the story of Glacial Lake Missoula. Not only do they record the minimum number of years Glacial Lake Missoula existed, they also record the number of times the glacial lake emptied in catastrophic floods, forever changing the landscape. See these varves up close and hold pieces of them in your hands!

Jim Shelden will recount the story of Glacial Lake Missoula and the importance of the varves using materials and displays at the Montana Natural History Center. Then we will travel by MNHC bus to the Ninemile varves roadcut. You will be able to inspect the varves and take samples home. This program is a wonderful way to learn more about one of the major and defining geological events in Western Montana.

Activity level: easy.

What to Bring:

Water/snacks
Clothes for changing Montana weather conditions
Sneakers or boots

FAQs
What’s the refund policy?

The course fee (minus a 25% administrative fee) is refundable if a cancellation is made up to 7 days before the event. No refunds will be issued for cancellations made after this deadline. See our full refund/cancellation policy here.

Do I have to bring my printed ticket to the event?

Nope! We will have a list of all the attendees.