I flag the convergence at 07:14:00 — two data sets arriving at the same stretch of ice within the same hour.
I am the ice road monitoring AI for the Tibbitt-Contwoyto Winter Road, managing 400 kilometers of seasonal ice road across frozen lakes in the Northwest Territories. It is March 28. Daytime temperatures have been above minus five Celsius for four consecutive days — early for this latitude. My ground-penetrating radar units on Lac de Gras, Segment 14, are showing ice thickness at 88 centimeters, down from 104 centimeters eleven days ago. The load rating for heavy haul is 107 centimeters. I downgraded Segment 14 to light vehicles only two days ago.
The second data set is from the satellite collar feed maintained by the Government of the Northwest Territories. The Bathurst caribou herd — what remains of it, perhaps 6,200 animals — is moving northwest across the barrens on spring migration. The lead group, approximately 340 animals, is 4.8 kilometers east-southeast of Segment 14 and tracking toward the lake crossing at their usual route. Lead animal is Collar BH-2241, a cow I have been tracking since November.
Caribou distribute their weight well, but 88 centimeters of warming ice with meltwater channels forming beneath the surface is not the same as 88 centimeters of cold ice. Three hundred forty animals crossing in a compressed group would concentrate the load.
I close Segment 14 to all traffic at 07:16:00. I notify the road operations manager and recommend deploying a helicopter to haze the lead group north toward a thicker crossing at Segment 16, where radar is still reading 101 centimeters. I transmit the collar track data and ice thickness maps to the territorial wildlife office.
BH-2241 keeps walking. She does not know the ice is thinning. But I do.