Ef slyddan byrjar aftur og skúrirnir verða meiri, tek ég strætó heim.

This is very normal in Icelandic. The present tense is often used for future meaning when the context already makes it clear.

So:

• Ef slyddan byrjar aftur ... = If the sleet starts again ...
• tek ég strætó heim = I’ll take the bus home

English also does something similar in the if-clause:

• If it rains, I’ll stay home

Notice English also uses rains, not will rain, after if. Icelandic does this even more broadly, including in the main clause here.

Because Icelandic usually follows the V2 rule: the finite verb tends to come in the second position in a main clause.

Here, the whole if-clause comes first:

• Ef slyddan byrjar aftur og skúrirnir verða meiri, ...

After that fronted clause, the main clause begins, and the finite verb comes first:

• tek ég strætó heim

So the structure is roughly:

• [If-clause], [verb] [subject] ...

If you started with the subject instead, you would normally say:

• Ég tek strætó heim ef slyddan byrjar aftur ...

But once the subordinate clause is placed first, tek ég is the expected order.

The endings show the definite article attached to the noun:

• slydda = sleet

• slyddan = the sleet

• skúrir = showers
• skúrirnir = the showers

Icelandic often uses the definite form in weather statements when talking about the weather conditions currently being discussed or already understood from context.

So this sentence is not talking about sleet and showers in general, but about the sleet / the showers in the situation at hand.

They do match — but each verb matches its own subject.

• slyddan byrjar

  • subject: slyddan = singular
  • verb: byrjar = singular

• skúrirnir verða meiri

  • subject: skúrirnir = plural
  • verb: verða = plural

So the difference comes from singular vs. plural subjects, not from tense.

Meiri is the comparative form of mikill, which often means much, great, or large, depending on context.

Here meiri means something like:

• greater
• more intense
• heavier

So skúrirnir verða meiri is literally something like:

• the showers become greater

but in natural English that becomes:

• the showers get heavier
• the showers intensify

This is a good example of how Icelandic sometimes uses a more literal more/great type adjective where English would use a weather-specific adjective like heavier.

Because strætó here means bus in a general transport sense, like take the bus in English.

So:

• tek strætó = I take the bus / I go by bus

This often sounds more natural when you mean the mode of transport, not one specific bus.

If you said:

• tek strætóinn

that would more strongly suggest the specific bus, as in a particular bus that has already been mentioned or is obvious in the situation.

Also, taka takes the accusative case, and strætó here is the accusative form.

Because heim is an adverb meaning home or homewards.

So:

• fara heim = go home
• koma heim = come home
• taka strætó heim = take the bus home

This is similar to English, where we also usually say go home, not go to home.

If you wanted to say at home, that would be different:

• heima = at home

So:

• heim = motion toward home
• heima = location at home

Aftur means again.

So:

• slyddan byrjar aftur = the sleet starts again

Its position here is very natural: it comes after the verb byrjar. Icelandic adverbs are fairly flexible, but this placement is common and straightforward.

No. Here ef is followed by the indicative, because the condition is presented as a real or possible situation.

So we get:

• Ef slyddan byrjar aftur ...
• Ef skúrirnir verða meiri ...

This is similar to ordinary real-condition sentences in English:

• If it rains, I’ll take the bus

The subjunctive is not needed just because a sentence begins with ef. In a sentence like this, the indicative is the normal choice.

The comma separates the subordinate if-clause from the main clause.

So the structure is:

• Ef ... , tek ég strætó heim.

This is very common when a subordinate clause comes first. It helps show where the main statement begins.

You can think of the sentence as:

• If X happens, then I take the bus home.

The comma marks that boundary clearly.

Yes. The sentence has one if-clause, and inside it two linked parts:

• slyddan byrjar aftur
• skúrirnir verða meiri

joined by og = and

So the condition is:

• if the sleet starts again and the showers get heavier

Both things belong under the scope of ef. The main clause only comes after the comma:

• tek ég strætó heim

So the sentence means that those weather developments together lead to the speaker’s decision.