Means 'there is a risk/fear/danger that ~'. It warns that some undesirable event may occur. Used for objective, somewhat serious possibilities, so it is common in news, weather reports, and formal notices rather than casual conversation.
[Verb dictionary form] + おそれがある / [Noun] + の + おそれがある
台風が上陸するおそれがある。
Taifuu ga jouriku suru osore ga aru.
There is a risk that the typhoon will make landfall.
Verb 上陸する + おそれがある warns of a possible undesirable event.
この地域では大雨のおそれがあります。
Kono chiiki de wa ooame no osore ga arimasu.
There is a risk of heavy rain in this area.
Noun 大雨 + の + おそれがあります, typical of weather warnings.
対応が遅れると、被害が広がるおそれがある。
Taiou ga okureru to, higai ga hirogaru osore ga aru.
If the response is delayed, there is a danger the damage will spread.
Verb 広がる + おそれがある flags a serious potential negative outcome.
• Only for negative/undesirable possibilities. • Attaches to verbs (dictionary form) and nouns (+ の); い-adjectives are used via their verb form (e.g. 高くなるおそれ). • Register: formal / written; common in news and official warnings. • Do not use for good possibilities — use かもしれない instead.
The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones ~おそれがある is tested against.
かもしれない is a neutral, casual 'might' for any outcome; おそれがある is formal and only for undesirable, worrying possibilities.
可能性がある is neutral about whether the outcome is good or bad; おそれがある specifically warns of a bad outcome.
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