Fat tires are very 'spensive. Certified Problem Solver "El Gato"sends in this report from the field: 

Ultra-mean tire gash. Does this mean $100+ dollars down the drain? 

Nah. We got this. 

A view from the inside

Cut yerself an appropriately sized bit of spare inner tube


Glue: spread it on

Patch it. 

Ensure adhesion. 

At last report, this solution has held up for 2 months of winter riding so far. Nice work Gato!