NORWICH — Two seasonal Upper Valley events will not happen as planned this weekend.

The Montshire Museum of Science has canceled its annual Igloo Build, which was scheduled to take place this Saturday.

The cancellation was motivated by the lack of sufficient quantity and quality of snow.

“Despite the appearance of ideal snow currently on the ground, this season has produced infrequent and insufficient snowfalls,” according to a statement posted to the Norwich-based science museum’s website. “Additionally, the multiple freeze/thaw cycles have caused the ice crystals to metamorphose, and the rain has saturated the snow, causing the snow to lose much of its strength.”

The lack of strength makes the snow difficult and unsafe to cut and stack into igloos.

In place of the igloo building, the Montshire will host a snow sculpture carving event. It will have blocks of snow and tools available for participants to carve into shapes. More information can be found at montshire.org.

Additionally, Hartford’s Recreation and Parks Department has postponed its Youth Ice Fishing Derby. The annual event, which was set to take place Saturday, has been tentatively rescheduled to March 2.

The ice on the pond is not thick enough to safely host the derby, according to a news release from the department. Currently, the pond has around 3 inches of black ice and 2 to 3 inches of white ice, which is weaker than black ice, on its surface.

“To safely hold the event, there needs to be a minimum of 4 inches of black ice,” according to the statement.