Eilen oli virtakatko koko korttelissa, ja nettiin tuli häiriö heti.

Yesterday there was a power outage in the whole block, and the internet had a disruption immediately.

Breakdown of Eilen oli virtakatko koko korttelissa, ja nettiin tuli häiriö heti.

• olla: to be
• ja: and
• -ssa: in
• tulla: to come
• eilen: yesterday
• -iin: to
• heti: immediately
• koko: whole
• netti: the internet
• kortteli: the block
• virtakatko: the power outage
• häiriö: the disruption

Questions & Answers about Eilen oli virtakatko koko korttelissa, ja nettiin tuli häiriö heti.

Why does the sentence start with Eilen?

Eilen (yesterday) is a time adverb, and Finnish often places time (or place) at the beginning to set the scene. It also helps the listener immediately know the tense/context. The rest of the clause still works the same: Eilen oli virtakatko... = Yesterday there was a power outage....

Why is it oli virtakatko instead of something like virtakatko oli?

This is a very common Finnish existential/“there is/there was” pattern:
(time/place) + olla + (new thing that happened/appeared)
So Eilen oli virtakatko is like There was a power outage yesterday.
You can say Virtakatko oli eilen, but it shifts emphasis to virtakatko (talking about it as an already-known topic).

What exactly does virtakatko mean, and how is it formed?

Virtakatko means a power outage / power cut. It’s a compound:

• virta = (electric) current / power
• katko (from katkaista) = a cut/break
  Together: a break in electrical power.

What case is korttelissa, and why that case?

Korttelissa is in the inessive case (-ssa/-ssä), meaning in.

• kortteli = (city) block / block of buildings
• korttelissa = in the block
  So koko korttelissa = in the whole block (i.e., throughout the whole block).

Does koko korttelissa mean the whole neighborhood?

Usually kortteli is more specific than neighborhood: it’s typically one city block (a block of buildings bounded by streets). In casual speech, it can feel a bit broader, but the core meaning is still block rather than an entire district.

Why is koko not in the same case as korttelissa (why not kokossa or something)?

Koko is an adjective meaning whole/entire, and adjectives agree in case/number with the noun—but koko is special: it often appears in this fixed-looking form koko + noun. The case ending shows on the noun:

• koko kortteli (nominative)
• koko korttelissa (inessive)
  This is normal and idiomatic.

Why is there a comma before ja?

Because it connects two independent clauses:
1) Eilen oli virtakatko koko korttelissa
2) nettiin tuli häiriö heti
In Finnish, you typically use a comma before ja when it joins full clauses (not just words/phrases).

What does nettiin mean grammatically, and why that form?

Nettiin is illative (-Vn / -in / -seen), roughly meaning into / to.

• netti = the internet (colloquial)
• nettiin = to the internet / into the internet connection (idiomatically: the internet service/connection)
  So nettiin tuli häiriö literally A disturbance came to the internet, i.e. the internet connection got disrupted.

Why use tuli häiriö instead of oli häiriö?

Tuli (from tulla, to come) often expresses a change of state / something starting suddenly: a disturbance appeared/started.

• nettiin tuli häiriö = a disturbance occurred / started (onset)
• netissä oli häiriö = there was a disturbance (state/ongoing situation)
  Both are possible, but tuli highlights that it happened right then.

Why is it häiriö (nominative) and not häiriötä (partitive)?

With existential-type sentences, Finnish often chooses between nominative and partitive depending on meaning:

• häiriö (nominative) suggests a specific disturbance event (countable, bounded)
• häiriötä (partitive) would suggest some disturbance / ongoing disturbance / an unbounded amount
  Here tuli häiriö heti sounds like one disturbance started immediately.

Where does heti fit best, and could it move?

Heti (immediately/right away) is flexible, but position changes emphasis slightly. All of these can work:

• ... ja nettiin tuli häiriö heti. (neutral: it happened immediately)
• ... ja heti nettiin tuli häiriö. (emphasizes immediately)
• ... ja nettiin heti tuli häiriö. (also emphasizes immediately, slightly more spoken) The given version is very natural.