This URL contains special characters, which Ruby can't handle:
```ruby
>> URI.parse 'http://www.yr.no/sted/Finland/Västra_Finland/Askainen/varsel.xml'
URI::InvalidURIError: bad URI(is not URI?): http://www.yr.no/sted/Finland/Västra_Finland/Askainen/varsel.xml
from /usr/local/lib/ruby/1.8/uri/common.rb:436:in split'
from /usr/local/lib/ruby/1.8/uri/common.rb:485:in parse'
from (irb):5
```
Your browser can probably open the URL. To fix this error encode the URL before handing it to the parse method:
```ruby
URI.parse(URI.encode('http://www.yr.no/sted/Finland/Västra_Finland/Askainen/varsel.xml'))
=> #
```