Chris: 31 px/1.7526 meters (He is 5 feet and 9 inches according to this)
Plane height: 260.5 px/14.7274935484 meters
Plane height: 81 px/14.7274935484 meters
Explosion base: 289 px/52.5462424134 meters (26.2731212067 meters for the radius)
26.2731212067^3*((27136*1.37895+8649)^(1/2)/13568-93/13568)^2 is 1.4575401383 tons, or Building level+
However, there was a distance Sierra was away from the explosion, hence Inverse Square.
Sierra: 248 px/2.032 meters (from the chart linked above earlier)
Distance she was from the explosion: 494 px/4.04761290323 meters
(1.4575401383) / (4π((4.04761290323)^2)) is 0.00707966512 tons/m^2
Using a Human Body Surface Calculator and inputting Sierras height and weight based on her height, the result is 2.199 m^2. Since its half of her body taking it, that is 1.0995 m^2
0.00707966512*1.0995 is 0.00778409179 tons, or Small Building level