Creating flt (floating point grid) files for use in RAS Mapper

[longers]

Can anyone suggest a tool for converting DEMs to flt files? The flt file extension refers to a "floating point grid" file. RAS Mapper uses files of this type for terrain when mapping HEC RAS outputs.

I understand that this file type is associated with ESRI Arc GIS - is there any way for someone without access to Arc GIS to create these types of files?

Alternative, does anyone know the format of these files (I figure that if I know that, I may be able to write a script that converts DEMs to flts). Is anyone able to post an example of a flt file?

Thanks