It is a truth, universally acknowledged, that every British journalist when faced with a
disaster such as a forest fire, flood, earthquake, tidal wave or hurricane that has
created widespread devastation of a sufficently noteworthy extent, will inform us that an 'area
the size of Wales' has been subjected to said devastation.
If the facts warrant it, the journalist may refer to multiples of this standard unit of measure
such as an 'area twice the size of Wales' or even occasionally to fractions thereof, such as an
'area half the size of Wales'. The reasons for this are uncertain but are probably something to do
with the fact that Wales is quite small but still, in the minds of a British audience, counts as
a 'whole country', and therefore sounds like an impressively large area. Although no matter how
big or small the area efffected no one will ever refer to an 'area the size of Hampshire' or an
'area the size of Scotland'.
The ever helpful Wales-o-meter at http://www.users.globalnet.co.uk/~kelky/sk/sizeofwales.html
will help you calculate the size of your chosen area relative to the universally accepted standard of Wales.
Note for American readers for Wales substitute Massachusetts.