Noun: Clatter, crash.
In our example headline, rytinä appears in the adessive singular, rytinällä. (See rytinä fully declined here.) Adessive case can used to say something is ”on” something; ”in,” ”at” or ”on” a place without a roof; ”in” or ”during” some period of time; or ”by” or ”with” something, in the sense of how it’s done. (Finnish for Busy People has a great summary of adessive use here.) In our example, the translation into English would be ”with a clatter,” or even better, the idiomatic ”with a bang.”
Note: the correct way to translate adessive case into English is tricky and can also be difficult for native Finnish speakers to know which preposition to use when speaking English. Native English speakers typically pick these prepositions simply ”by ear.”
Let’s translate the whole headline, ”Helle tuli rytinällä Lappiin.” (You can read the whole article online here, if you like.)
Helle is a noun that means ”heat.”
Tuli is the 3rd person past tense of tulla, which means ”to come.” Tuli means ”came.”
Lappiin is the illative singular form of Lappi, which is a geographical area that covers the northernmost parts of Norway, Sweden and Finland plus a Northwestern corner of Russia. In the illative it means ”to Lapland” or ”into Lapland.” (Finnish for Busy People also has a great guide to illative case here.)
Our whole phrase in English might be ”Heat came with a bang to Lapland.”