A lot of the early, absolute advantages of Fortran (numerical precision, non-aliasing) has been adopted by C.

However what still makes it a great choice is that it still a relatively simple language compared to C, and maps mathematical formulas to code very well. Inelegant code will still run reasonably fast (which is not the true with C) - so all of these points make it actually a good language when the program is being written by domain experts (i.e., scientists) rather than professional programmers or software engineers.