haroukeihou ni ouzite, syukuhakuentyou wo suru.

A natural reading is:

はろうけいほう に おうじて、しゅくはくえんちょう を する。

Word by word:

• 波浪警報 = はろうけいほう = high wave warning / wave warning
• に応じて = におうじて = in response to / according to
• 宿泊延長 = しゅくはくえんちょう = extension of a stay / lodging extension
• をする = to do / carry out

に応じて means something like:

• in response to
• according to
• depending on
• in accordance with

In this sentence, it means the action is taken because of or in response to the wave warning.

So the nuance is not just simple cause-and-effect like because there is a warning. It suggests adjusting one’s action to match the situation.

In A に応じて, the に marks the thing that the response is based on.

So:

• 波浪警報に応じて = in response to the wave warning

This pattern is fixed:

• 状況に応じて = according to the situation
• 年齢に応じて = according to age
• 必要に応じて = as needed

So the に is not random; it is part of the grammar pattern N に応じて.

Both are understandable, but they are slightly different in structure.

• 宿泊延長をする = to do a stay extension
• 宿泊を延長する = to extend the stay

宿泊延長 is a noun, almost like an administrative label: stay extension. Adding をする turns that noun into an action.

This kind of wording often appears in:

• notices
• manuals
• hotel procedures
• official or business-style writing

For everyday speech, many learners may find 宿泊を延長する more straightforward and natural.

Yes, but it sounds brief, formal, and somewhat administrative.

It feels like the kind of wording you might see in:

• a policy note
• a disaster-response guideline
• a hotel or travel procedure
• a checklist item

In normal conversation, a speaker might say something more like:

• 波浪警報が出たので、宿泊を延長する。
• 波浪警報に合わせて、滞在を延長する。

So the original sentence is natural, but it is not especially casual or conversational.

Japanese often leaves out the subject when it is clear from context.

So this sentence does not explicitly say:

• who is extending the stay
• whose stay is being extended

Depending on context, it could mean:

• we will extend the stay
• guests should extend their stay
• the hotel will arrange an extension of accommodation

This is very normal in Japanese, especially in short written statements.

The comma simply marks a pause and helps readability.

The sentence structure is:

• 波浪警報に応じて = in response to the wave warning
• 宿泊延長をする = extend the stay

The comma is not required every time, but it is common when the first part is a longer modifier or setup.

So:

• 波浪警報に応じて宿泊延長をする。
• 波浪警報に応じて、宿泊延長をする。

Both are possible.

Not exactly. 波浪警報 is specifically a high wave warning.

Breakdown:

• 波浪 = waves / sea waves
• 警報 = warning

So this is not just any weather alert. It specifically refers to dangerous wave conditions, usually related to the sea or coast.

Yes, that can work, but the best English depends on context.

Possible translations:

• Extend the stay in response to a high wave warning.
• Extend the stay according to the high wave warning.
• Extend the stay depending on the high wave warning.

Of these, in response to is usually the most natural for this sentence, because a warning is something you react to.

Depending on is possible, but it can sound a little less direct in English.

No, normal Japanese is usually written without spaces.

Standard writing would be:

波浪警報に応じて、宿泊延長をする。

The spaces in your example were probably added:

• to help learners read it
• to show word/group boundaries
• to make the sentence easier to parse

So the spaced version is a teaching aid, not standard Japanese spelling.